Kind of depends on what you're checking for. Epp's smithy has a $30 minimum shop charge.
A bore scope is just a flashlight with a bent plastic lens. It's not a big fancy high priced machine, if that's what you're thinking.
You can check a barrel yourself with any flash light. Helps to put a wee piece of paper at the chamber end to reflect light. Your thumb works to reflect light too.
You're looking for sharp, clean, rifling and no obvious damage or rust spots.