$35 would be nothing when you consider how much it helps the band to be able to use a quality kit that is tuned properly, and also it means they don't have to lug their kit in, saving them more trouble. I'd maybe even charge more. Also be sure to employ a "you break it you buy it" policy. This might be a bit exreme, but have the caveman inspect all the cymbals for cracks (if he's using yours) with you before he starts thrashing on them, so you can both agree that the cymbals are fine. After he's done, have another cymbal inspection, and if any are damaged you can maybe ding him a bit for that, too. Within reason of course, as cymbals are prone to breakage at some point or another.
Damn I'm kind of a cheap bastard now that I'm broke all the time, haha.