From cars to calories and from babies to budgets, the federal government long has been a major publisher and distributor of free or low-cost consumer information.

In the last four years, however, Uncle Sam's distribution of booklets and pamphlets through its clearinghouse, the Consumer Information Center, has plummeted about 77 percent, from its 1981 peak of 26 million publications to just 6 million last year. Officials say the decline stems from Reagan administration budget-tightening actions, which have included raising the price of many government publications, eliminating some free brochures and initiating a new $1 fee for anyone ordering two or more of the remaining free publications.

"This did result in a drop in orders, because people were upset by these fees . . . because they weren't used to paying them," said CIC representative Tim Burr.

Consumer activists have criticized the center's pricing policies, saying they have hurt the people they are supposed to help. "While the Reagan administration has taken the position that consumers must protect themselves in the marketplace, they aren't giving consumers the information they need to do that," said Clarence Ditlow, director of the Center of Auto Safety, a consumer activist group.

Distribution has fallen so low that the CIC, established in 1970 to help federal agencies promote and distribute useful information to consumers, has launched a promotion to remind the public that it is still in business.

The promotion is the work of the center's 20-person Washington staff, which has remained constant since 1981 despite the fall in distribution. The CIC's Pueblo, Colo., distribution staff is down from 100 workers in 1981 to 50 today. The CIC is part of the General Services Administration.

As part of the effort to increase distribution, the CIC has produced public service announcements declaring that "you can count on the Consumer Information Catalog to turn you on to new ideas that help solve problems and brighten your world." CIC also has added some color -- green, as in money -- to jazz up the catalog, which previously was black and white. In addition, the CIC has tried to downplay the importance of price increases by describing as "quite a bargain" the $1 fee now required of consumers ordering two or more free booklets.

But the promotion can't cover up these facts:

* About 70 percent of the publications listed in the 1981 catalog were free, compared to 50 percent today.

* The center's all-time best seller -- "The Car Book" -- no longer is available. The book, which was distributed free through the center to about 1 million consumers in 1981, was dropped after President Reagan took office. Jack Gillis, who compiled the book for the U.S. Department of Transportation, left his job and has continued to publish it privately with help from the Center for Auto Safety.

* Some free publications dropped from recent catalogs have been reintroduced, but they are no longer free. "How to Buy Economically: A Food Buyer's Guide," compiled by the U.S. Department of Agriculture, was offered free through CIC until 1983, when it disappeared from the catalog. The guide has reappeared in the 1985 catalog and now costs 50 cents.

* In 1981, the most expensive publication in the catalog cost $2; today, the top price is $7.

To order a catalog, write to the Consumer Information Center, Pueblo, Colo. 81009. Consumers should act now while the catalog is still free.