As another reviewer put it, Cheapo Discs really is the granddaddy of all record stores in Austin. You can find new CD's in this store easily, but what you really go in there for are their used CD's. And there's not really a "Used Section" because just about their whole store is used CD's. You'll find some really great deals here on music that you might not be able to find anywhere else.
You do need to be a bit patient because the amount of CD's to look through can be overwhelming but it's worth it. If you've never been here and want a "brief" on what type of music they carry, just look through their Recent Arrivals section. It's several bins long but it's fun.
You can also find used records and DVDs. Definitely my favorite music store in Austin.