Outside of California (which has its own complicated reasons for fee structure), the going rate is probably 20 to 35 dollars. However, 50 dollars is not entirely out of line or unheard of. A lot depends on the nature of a business. A part time hobbyist might charge less since they're not feeding their family or having to keep the lights on. A store might charge more since they have overhead.

Gander Mountain charges - last I checked - 35 bucks.