美國 / old/used clothing... what to do?

In Arizona, we have a store called "Buffalo Exchange". They buy used clothes. What they do is if they decide to sell your shirt at $10, they will give you $3.50 cash (35%).

I know they have locations in San Francisco too, I am not so sure about LA. You can probably look into it. :)

Try second hand store on Melrose. I don't know the pirce .. One of my friend had done this before.

You can go to a store named "Wasteland" on Melrose. They sell and also buy secondhand.
As my experience, they only want "brand-name" stuff. I sold a pair of Diesel jeans to them and they gave me about 25 dollars. So you can tell how they deal with this.

德州達拉斯有..我去賣過很有趣.還賣了不少錢哩..我看很多老外搬了一堆爛爛的鞋子也拿去賣喔^_^