It varies depending on the agency, the scope of the request and the purpose of the request. For just one example, here's the State of Illinois FOIA FAQ:
Taxpayers already do with their contribution to the country budgets, in EU you can submit FOIA for free to governments entity and to any private company who received government funding, it's a matter of public interest and if you receive my money (as taxpayer) then you put into account the fact that as a citizen I might request some answers
