Should users (like trucks) pay for what they get (like roads)?

Depending on who you talk to, user fees are either a ''revenue enhancement'' whose time has come, or a tax by any other name. The Reagan administration has made it clear that it wants those who benefit from services or facilities provided or maintained by the federal government to start helping foot the bills for such costs by paying user fees.

User fees have existed for years, but mainly as minor charges for such things as fishing licences and campground fees. Only recently has the concept been broadened to include a host of federally subsidized services such as the Coast Guard, airports, highways, and ports.

When the idea for a wider application of user fees was first broached shortly after President Reagan took office, Congress balked at the plan. Potential sponsors of user fee legislation smelled a thinly disguised tax and most of the proposals were promptly shelved.

Since then, and following an early fall speech in which the President reiterated his position on user fees, Congress has, in the words of one Budget Committee aide, slowly ''come around to the idea on general principles,'' though few lawmakers have committed themselves to specific proposals.

Yet, the Reagan administration may force more serious consideration of the user fee plan. A spokesman for the Office of Management and Budget says, ''We plan to submit a long new list of (user fee proposals) to Congress in January.'' This, combined with continuing budget deficits and declining revenues due to tax cuts, may induce lawmakers to give the President's plan more than a cursory glance.

Only a few of the user fee proposals have evolved into draft legislation, but those being addressed seriously revolve around:

* The Coast Guard. A plan to be unveiled in December will most likely include draft legislation calling for: federal registration of recreational boats accompanied by a sliding-scale fee based on the size of the vessel; and a tax on motor boat fuel. The administration wants the fees to eventually offset 33 percent of the operating cost of the Coast Guard by generating up to $400 million in revenue by 1984.

* Highways. Hearings have been held in the Senate on a proposal to raise the taxes levied on trucks that use the Interstate highway system. Railroad associations and other groups complain that the trucking industry is artificially subsidized by a highway network built and maintained by the federal government.

* Airports and Highways. The administration wants to raise the aviation fuel tax from 4 cents a gallon to 12 cents a gallon, and raise the passenger tax paid on tickets from 5 percent to 6.5 percent. In both cases, figures proposed by the administration were scaled back this summer when the initial suggestions ran into heavy opposition. A $3 per head international departure tax has also been suggested.

* Ports and Waterways. Legislation has been introduced in these areas that would impose fees on ship and barge operators designed to recover 100 percent of the cost of port maintenance and help finance projects such as dredging one or more ports to 55 feet for coal exporting ships.

Industry trade groups and recreational interests have raised their voices in a collective howl of protest over plans for charging new or increased user fees.

The negative reaction is directed not so much at the fees themselves but at what is perceived to be their inequitable distribution and the fact that the amount of money collected through fees often isn't the same amount doled out in services.

''We have no outright opposition to the user fee proposal,'' says Derrick Crandell of the American Recreation Coalition. His primary concern is that ''no new fees be imposed until a system is devised to provide utilization of those funds.''

In cases where user fees are paid into trust funds established for the maintenance of such things as highways and ports, there is a built-in guarantee that Congress will pump the fees back into those facilities. But in the case of user fees charged to recreational boaters, for instance, there is no such guarantee that the exact amount collected in fees will be repaid to boaters in the form of Coast Guard services.

The result is widespread suspicion among those affected by the fees that some of the charges are designed solely for the purpose of providing the government with additional revenue.