Ronald Reagan's talk wasn't cheap.

He charged savings-and-loan executives $10,000 for one speech. Florida lumber dealers paid him $8,000 for another. The turkey industry, in turn, scratched up $7,500.

Even the Boy Scouts had to be prepared -- to pay a fee of $5,000.

In all, Reagan received about $1 million for his speeches and commentary during nearly two years of undeclared campaigning before his formal entry into the presidential race last Nov. 13.

Although he was already a wealthy man, Reagan toiled assiduously at his profitable enterprise, giving 128 paid speeches in 22 months. He spoke to bankers, chiropractors, surgical-instrument salesmen and dentists. He addressed egg producers, Taiwanese businessmen, insulation contractors, highway lobbyists and the National Association of Truck Stop Operators.

All this was entirely proper. And Reagan's fees weren't any larger than those commanded by such figures as Gerald Ford, Alexander Haig and Arthur Burns, whose speeches aren't half as entertaining as Reagan's.

Furthermore, nobody has contended that the business and professional groups that paid Reagan large fees were trying to influence his policy positions. Reagan's views have been unshakably pro-business since the 1950s; in speaking to these groups, he was preaching to the choir.

An examination of Reagan's speaking business reveals his as a man with a keen eye for the dollar. His basic fee doubled last year, jumping to $10,000 when his managers discovered that others were getting that much. Earlier Reagan charged $5,000 each for appearances at 12 GOP fund-raising events -- which left some Republicans miffed.

"He was running, for president and charging us for it," says H. G. Taylor, Republican chairman of Macon County, Ill. Taylor calls it the only time in his 30 years' experience in politics that a party figure wanted money to appear at such an affair. Richard Nixon and John Connally spoke without charge, he recalls.

Once, local Democrats raised a fuss when Reagan charged a fee to address a United Way charity fund-raising function in the Midwest. Michael Deaver, the veteran Reagan political adviser who arranged his speaking schedule, doesn't recall the size of the fee or the exact site. He does recall that Reagan gave a rebate, but of only half the fee. "He was in the business of giving speeches," he notes.

He adds that the ex-governor of California was "sensitive" about charging for charity affairs and gave about 20% of all his speeches gratis. Reagan nevertheless accepted two fees for Boy Scout fund-raising appearances in California last year, $2,500 to address a San Gabriel Valley group and $5,000 for a talk in Bakersfield.

Reagan's financial success put him in demand at numerous investment seminars where the well-to-do paid several hundred dollars each to hear economic experts advise them what to do with their money.

Morgan Maxfield, a seminar impresario from North St. Louis, Mo., says Reagan received standing ovations at seminars last year in Dallas, Miami and New York. Maxfield recalls that Reagan, the son of an Illinois shoe merchant, related how he raised money as a boy by gathering empty pop bottles and returning them for their deposits.

Reagan also told how he did well by buying and holding stocks in the 1950s and 1960s, but he advised his listeners that volatile conditions at the time of the seminars made it more prudent to build liquidity, Maxfield says.

Reagan did well at building his own liquidity. After deducting expenses for staff salaries and such, he netted $296,102 last year -- and about the same amount in 1978 -- from his speaking engagements and, to a far lesser extent, from his radio program and newspaper column.

This income, together with investments in stock and real estate, has helped push Reagan's net worth to probably more than $2 million, up from 1.5 million at the end of 1975.

Being so prosperous, Reagan is likely to find the issue of his taxes arising in the fall campaign, as it did during the 1976 Republican presidential primaries. Attention focused then on his entirely legal but nevertheless politically embarrassing avoidance of all California state income tax in 1970.

This time Reagan will be pressed to match President Carter's example by publishing his federal income-tax returns. Reagan hasn't done so yet because of distaste for "invasion of privacy," aides say.

What would such a disclosure show? "I can guarantee you he didn't pay any more taxes than he had to," says his personal attorney and financial adviser, William French Smith. But Smith say his client has paid "substantial" taxes and that, while he has been audited more than once by the Internal Revenue Service, the reviews were "quite normal."

Taxes aside, Mr. Reagan's financial triumphs on the speaking circuit could become political liabilities this fall. The Democrats are considering whether to make an issue of the Republican candidate's speech-making income from business groups. "It's a marriage made on Wall Street," says one Democratic Party official, trying out a possible campaign zinger.

Such a tactic could backfire, however. "A lot of our Senators do the same thing," the same Democrat says.

Reagan stopped charging for speeches when he formally entered the presidential contest, but he can count on several continuing sources of income. He still gets $17,714.04 a year as a pension from the state of California. He receives interest on aBeverly Hills bank account, an account that probably amounts to more than $500,000. And he gets more than $50,000 a year in interest on a mortgage he holds on a 771-acre ranch he sold a few years ago for over $750,000.

Though it pays no current cash returns, the real estate Reagan still owns is worth more than $1 million, and its value is apparently rising.

His 688-acre Rancho del Cielo in Santo Barbara County was purchased in 1974 for $526,000. It is difficult to estimate how much more the property is worth today because special taxing provisions prohibit its development for at least another 10 years. The ranch still carries a mortgage of more than $250,000 at an attractive 8% annual interest.

The Reagan home in Pacific Palisades, paid off several years ago, is easily worth $500,000. Neighboring houses fetch around $1 million.

But Reagan now holds little or no corporate stock. He sold almost all his holdings last year for more than $750,000. The money went into that Beverly Hills bank account, although some way have been withdrawn this year to pay capital-gains taxes on the sale.

Among the stocks sold were more than $250,000 in Continental Illinois Properties, $100,000 in First Union Bancorp., more than $100,000 in Western Bancorp. and lesser holdings in Archer-Daniels-Midland Co., Dart Industries Inc., Detroitbank Corp. and some other companies.

Did Reagan sell to eliminate possible conflicts of interest? He may have been just taking his own investment advice.

Maxfield, the investment adviser, says Reagan was predicting a collapse of auto sales as long ago as October 1978, well before the auto slump materialzed, and was predicting a sharp housing decline as early as last September, two weeks before the Federal Reserve Board began credit-tightening moves that sent home-mortgage rates skyrocketing to unaffordable levels. Reagan counseled that in such times "liquidity is an important thing," Maxfield recalls.

So the personal forecasting of Reagan, who once studied economics at Eureka College in Illinois, today sounds pretty good. He got big fees for talking, but he put his money where his mouth was.