An economic concept known as the "user fee" is all the rage in federal budget circles these days as executive agencies step up the search for new ways to cut the budget. The "user fee"--in which people are billed for government services that used to be supported out of general tax revenues--helps balance the budget because it brings in revenue and because it tends to reduce demand for the government service.

Here are some examples of federal agencies that have proposed initiating or increasing user fees when the new fiscal year begins:

* The Agricultural Marketing Service will charge tobacco firms 4 1/2 cents per 10 pounds for federal inspection and grading services that have traditionally been free.

* The Federal Energy Regulatory Commission will impose a new search fee of $8 to $16 per hour for tracking down papers requested under the Freedom of Information Act.

* The Federal Grain Inspection Service will raise fees for rice inspections.

* The National Archives will raise its fees for prints of historic photos and copies of video and audio tapes.

* The Agriculture Economics and Statistics Service, which used to put out daily market news on a taxpayer-supported 800 telephone number, has switched to a 900 number (900-976-0404) under which the government pays nothing and callers pay the Bell System 50 cents for each call.