I know a guy that purchased a Hawkeye and he said he can't believe he waited this long to pick one up. It has completely changed his cleaning procedure, and truly provided amazing insight into what's going on inside the bore. You get what you pay for with Bore Scopes, and Hawkeye is the gold standard. Plus, resale value is amazing with them.
If you go with one of the cheaper bore scopes, the image quality won't be the same. Think about it, you're bore scoping to see minor details within a rifle barrel, so you want the best resolution possible. Without spending thousands on some fancy system, Hawkeye is the best bet. $775 from Sinclair is not a bad deal (with focusing eyepiece). You could also look for a used one, but I doubt you'll find anything under $500.
It's the same story with anything in this sport...buy once, cry once, but make sure you read as many reviews and test one out before you buy it. I'd be willing to bet that a gun shop within 100 miles of your place owns a Hawkeye and they'd probably let you check it out, if they are nice folks.