Like others have said, Pmags are great. I like the USGI D&H mags w/ Magpul followers. There may be others in this class. There are definitely worse. Buyer beware.
The next key is how to get them for $12 or less each. For that, you need to access the knowledge of AR15.com. I bought D&H for $11 each from BCM. PSA has them for an even better price when you buy 10.