Just ordered a 10-pack of 30-round AR-15 mags, and I don't even have an AR-15 at the moment. But I plan on getting one some time next year. I had to do it while prices are decent, and before any possible post-election hi-cap mag ban.
http://palmettostatearmory.com/index...mag-10405.html
Here's a good deal for anybody looking for some P-Mags:
http://dsgarms.com/ProductInfo/DSGHOLIDAYPK1.aspx