Places I have pruchased from recently
www.eabco.com
www.theopticzone.com
www.midsouthshooterssupply.com
www.midwayusa.com

ETA midway has a good deal on AR mags right now, they are out of stock but you can backorder.
http://www.midwayusa.com/eproductpag...eitemid=895719