I recently bought new tires for our classic car, b/c the tires were 8 years old and the sidewalls were starting to crack. We had them installed by a local a used tire shop with excellent yelp reviews and referred by our mechanic. They noticed that the spare tire was almost 20 years old, so we purchased a used tire for the spare.
While we were waiting for the tires to be put on the car, we had the chance to talk candidly with the owner of the used tire shop, as well as see the business. Lots of demand for used tires, and the owner provided a ton of flexibility in financing the purchase to his cash-strapped clientele. Who almost always showed up in an SUV or pickup truck, but that's a whole other story...
He was clearly a good guy, b/c a mom came in w/her kids and had one really bad tire but could only spend a very small amount. He couldn't help her, but he suggested another used tire shop and directed her to bargain hard w/him, and he even went on Craig's List & Ebay to see if he could find her a tire in her price range!
He's got my business for life - if I ever blow a tire, I'll go to him first to see if he has a decent option. I'm sure he's the exception and not the rule though, so do your research before working w/any local shop.