If you are looking for accommodations with charm, try a country inn. If a budget price is a more important consideration, one of the growing number of limited-service hotels and motels may be more appropriate.

Millions of vacationing Americans are expected to be on the road this summer -- taking advantage of the sharp drop in gasoline prices that makes a driving holiday a much better buy than in recent years. Many will save more money by checking into one of these lower-priced, no-frills lodgings.

About 50 lodging chains with an estimated 300,000 rooms in 3,000 locations operate limited-service hotels and motels, either regionally or nationally. It is "probably the fastest developing segment of the hospitality industry," said Dennis Fitzgerald, chairman of the Economy Lodging Council of the American Hotel and Motel Association. You can find one or more of the chains represented in every state, and they are proving increasingly popular with businesses looking for a way to trim expenses.

According to Fitzgerald, who also manages Imperial 400 Motor Inns, a hotel chain based in Arlington, budget travelers today can get the standard of facilities for which a decade ago they were paying mid-range prices.

Each chain's hotels tend to be look-alikes, no matter in what part of the country they are built -- a negative to some travelers and a comfort to others. But style isn't what these hotels and motels are promoting. Their basic aim is to provide a good night's sleep in a clean, modern room at low rates.

To cut costs -- and pass them along to the customer -- hotels drop the expensive frills. In most of them, you won't find a restaurant (though one usually is nearby), a bar, a large lobby or convention meeting rooms. No bellhop will tote your luggage; no basket of toiletries will await in the bathroom; it's doubtful antiques will decorate the room; and certainly no one will leave a fancy chocolate on your pillow at night.

At full-service hotels that do offer these amenities, "you pay for them even if you don't need them," said Jane Innes of Hampton Inns, a three-year-old budget-priced division of the Memphis-based Holiday Inn chain. Currently, there are 45 Hampton Inns -- mostly in the Southeast and Southwest -- and a new one is opening on the average of once every four days in 1986.

Another burgeoning chain, La Quinta Motor Inns, surveyed its clientele and concluded that the absence of a restaurant "really doesn't matter," said spokesman George Kauss. "The single most important thing they wanted is a clean room." Headquartered in San Antonio, the firm caters chiefly to business travelers. It now has 175 hotels -- all of them resembling a Spanish adobe hacienda -- and expects to have 300 by the end of the decade.

Dale Nichols, a spokesman for the 400-hotel Econo Lodge chain, headquartered in Charlotte, N.C., said he recently paid $66 to stay in a full-service hotel. "That's a lot of money just to lie down and go to sleep." His limited-service firm, which expects to be represented in all 50 states by the end of the year, quotes an average rate of $25 a night for a single room and $30 for a double.

Several of the leading budget chains say they can provide rooms at anywhere from 15 to 40 percent less than a full-service hotel or motel -- such as a Holiday Inn or Best Western motel -- in the same area. For most, the rates vary depending on the season and the location of the facility. The most expensive, as might be expected, are in or near big East and West Coast cities and at popular resort areas.

For example, Econo Lodge's rates this summer at its seven hotels near Colonial Williamsburg, a major tourist attraction, range from about $42 to $60 -- higher than the quoted $30 average but still much cheaper than the Colonial Williamsburg Motor House at the Visitor Center, where the summer rates begin at $71 a night.

One chain that does offer a flat rate throughout most of the country is Motel 6, a pioneer in no-frills lodging and generally regarded as one of the lowest priced operations in the country. Almost all of its 400 facilities charge $17.95 for a single room and $22.95 for a double. The rate for each additional person in the room is $2 for those 12 and older and $1 for children, ages 3 to 11.

For the price, the Motel 6 chain, based in Santa Barbara, Calif., provides what its officials describe as "somewhat of a spartan room" but one that is "immaculately clean." The room comes with two double beds and a private bathroom with a stall shower, but there's an extra charge of $1.49 a day to rent a color TV.

The chain currently does not have a central reservation number -- you must call each motel individually -- but it is contemplating one; it only recently began accepting credit cards; and it has just begun installing phones in rooms. On the other hand, most of the motels do have swimming pools -- as important as a TV set in sun-loving California, where one-fourth of the firm's properties are located. Among Motel 6's most-loyal guests are retired travelers, but in the summer it is families looking for low-cost rooms who make up a very large percentage of the guests. Apparently, they don't mind the missing amenities. In fact, a frequent complaint, according to officials, is that rooms are booked quickly "and people can't get in."

Some chains, though they do offer only limited services, are not exactly pleased to be grouped into the same category with Motel 6. La Quinta and Hampton Inns, for example, see themselves as much classier operations. For one thing, their rooms are anything but spartan -- and like most other chains, the rooms all have phones and you don't have to pay extra to watch TV.

La Quinta, in fact, prides itself on the quality of its rooms. "We've concentrated on a really upscale, well-decorated, squeaky-clean room," said Kauss, "with extra-fluffy towels and extra-long beds -- things to make a customer comfortable." The firm says its average rate is $40 a night for a single.

Many of the limited-service hotels are located near America's interstate highways -- convenient places to stop on the way to someplace else. But increasingly they are being built in downtown areas and at resorts and are attracting vacationers who spend several days or more.

Comfort Inns, a budget-priced offshoot of the Silver Spring-based Quality Inns chain, will soon be opening hotels in Manhattan and downtown Washington. Comfort Inns has 202 hotels and another 106 "under development."

Days Inn, a 300-hotel chain based in Atlanta, operates 20 properties in Orlando, home of one of the country's busiest tourist attractions, Disney World and Epcot. Rates this summer will range from about $53 to $76 a night for a double room at the hotels closest to the famous amusement park.

With the present exception of Motel 6, the larger budget chains have central reservations numbers, and most will mail directories of their properties on request. Among them:

Comfort Inns: Like several of the other chains, Comfort Inns says it emphasizes the quality of its rooms. "We're investing in the rooms as opposed to food and beverage, conference rooms and lobbies," said Joe Lavin, vice president for franchise development. Many Comfort Inns are found on I-95 south to Florida and in California. Lavin estimates the room rates at $15 to $20 less a night than for similarly located full-service Quality Inns. Children ages 16 and under stay free with their parents; (800) 228-5150.

Days Inn: Don't be surprised if you find a restaurant at a Days Inn; a number of the hotels have them. The chain is particularly popular with older travelers and has organized a September Days Club for individuals 50 and older. An annual fee of $10 entitles members to a 10 percent discount on room rates; a quarterly magazine; and access to discounts on last-minute cruises and other travel bargains. Some inns permit children under 18 to stay free; others charge from $1 to $3; (800) 325-2525.

Econo Lodge: Primarily located in the South, the chain promotes itself as low-cost lodging, "and we're trying to stay there," said spokesman Dale Nichols. About 60 percent of its winter guests are business travelers; in the summer, 70 percent are "traveling families on a traditional vacation in their car." Many Econo Lodges have swimming pools and about 30 percent have on-site restaurants. Children 11 and under stay free with their parents; (800) 446-6900.

Hampton Inns: "We offer an exceptional hotel room," said spokeswoman Jane Innes, along with a free continental breakfast, in-room movies and local phone calls -- at a price "20 to 40 percent below" what is charged by its parent chain, Holiday Inns. Hampton Inns sets aside 25 percent of its rooms for nonsmokers. Children 18 and under stay free; (800) HAMPTON.

Imperial 400 Motor Inns: Based in Arlington, this small but growing chain has 62 hotels concentrated mostly in the mid-Atlantic region and on the West Coast. It is seeking a business clientele, but its Washington hotels are popular with sightseeing visitors. Rates vary by location, but the average price for a room is about $32, said spokesman Dennis Fitzgerald. Children under 16 stay free; (800) 368-4400, in Virginia (800) 572-2200.

La Quinta Motor Inns: La Quinta is building its limited-service haciendas where business travelers congregate: office complexes, industrial parks, shopping centers, adjacent to university campuses. It estimates that 60 to 75 percent of its guests are business travelers. La Quinta, which is not a franchise operation like most of the other chains, prefers not to be known as a "budget" hotel but rather as one that provides a first-class room at mid-range prices. Outdoor swimming pools are standard, and there's complimentary coffee each morning in the lobby. Children under 18 stay free; (800) 531-5900.

Motel 6: Motel 6 has no problem with its budget image. It promises a cheap, clean place to shower and sleep -- and a courteous staff. If you want any extras, you probably will have to pay for them. The firm owns all the properties, enabling it, according to officials, to maintain its standards. Until it opens a central reservation line, you have to book with individual motels. For a directory, contact: Motel 6 Inc., 51 Hitchcock Way, Santa Barbara, Calif. 93105, (805) 682-6666.

Super 8: Super 8 is a fast-growing chain based in Aberdeen, S.D. Currently, it operates 336 English-Tudor motels in 39 states and is aiming for all 50. It plans to open 120 new motels this year, including several in the mid-Atlantic region. Back in 1974, when the firm was founded, the price of a room was $8.88 -- the reason for the name. Today, the average, according to spokeswoman Joy Krueger, is $28 for a single and $32 for a double. Most Super 8s permit children under 12 to stay free; (800) 843-1991.