I just buy whatever I think is comfortable, is cheap, and makes me look somewhat decent.

American Apparel's prices irritate the crap out of me. One ribbed tank top costs $17. Their hoodies are insanely expensive too. The only reason I've ever wanted to shop there is because their colour selection is huge, and I'd want my closet to look like a rainbow :(

(but seriously, they have such nice colours. Damn their $58734857 hoodies)