Sportsmans guide has a really good deal, let me get you the link...

http://www.sportsmansguide.com/cb/cb.asp?a=282484

6 for 50$
12 for 80$

Cant beat that anywhere.... they may be used but are 100% reliable, and genreally in pretty good shape. I have 40 of em i got em back when it was 20$ for 10 mags lol.

Anyways thats where i'd get em