Shibuya Book・off is one of my favorite place to go shopping.
You can get second handed books and CDs and etc there, but one of the biggest reason I like it is because of the low price. I bought three CDs and it didn't cost more than 1000yen. When I find something unexpected like old CDs that we can't see in CD shops, it makes me happy, and I think that is one of the enjoyable thing of going to second handed stores.