There is a difference, and there are tons of manufacturers. Just read some reviews on whatever you find a deal on. Can't go wrong with magpul. Brownells had Troy battlemags 3 for $25 and they are great mags fwiw. Ammo depends on what you want to do with it. Plinking, varmint, target, shtf? Want to keep brass for reloading? As for where... Midway has been hard to beat. Cheaper than dirt is good too! Palmetto state had some sales but think they are about over... Hope this helps
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