Suppose we pay for roads with a general per capita tax, simply divide total road cost by population. Now there is no incentive for any individual to economize on road use. Everyone pays, but everyone behaves like a free rider.

Suppose instead we pay for roads with a tax on gasoline. Now people who use roads more pay more. This seems more fair. People who don't use roads much don't pay much. But it's not perfect; people who buy gasoline for lawn mowers still pay for roads. People who drive electric cars will be free riders.

Self-supporting toll roads provide incentive to build and maintain roads where people want them, with no free riders (possibly with exceptions: free use for toll road employees, discounts for mass transit).

If I don't use the roads myself, but benefit because my trash removal company uses the roads, the trash removal company will include a portion of their road tax in my trash bill.

Your "contribute to the economy" language is vague. If someone benefits from a service, they ought to be willing to pay for it. It might be difficult or impossible to require payment, such as a bakery that can't bill neighbors for the pleasant aroma. Maybe that's not a good example. Can you think of a better, specific, example?