I started wearing them several years ago after having surgery to repair two hernias. I originally started wearing them for support around my surgical areas; now I can't play without them.
I got the cheapest I could find (unfortunately not from T-W) which were by Franklin for $12 at a local 'carry it all' superstore. They've lasted for a long time and are comfortable.
After microfracture knee surgery doc recommended I never play tennis again - been playing for 5 months now! Saving $$$ for APD'13 (x2)