I'm starting my first AR build and have been looking around for magazines, I want to get some 20 or 30 rounders before theres another ban and the prices skyrocket, can you guys give me advice on what ones are good at a decent price? I was planing on staying away from the polymer. So far I have found some made by Brownells for $10 each, can anyone tell me if these are good mags? These are cheapest I have found so far. Also what do you guys prefer, 20 or 30? 30s stick out farther so Im not sure if I'd like that. Thanks.