If cost is the primary motivator for sticking with aluminum mags, you can find Gen M3 PMags for under $11 a piece. Several forum members, myself included, have purchased 5-packs of tan mags from DSG Arms for $54 ($10.80 each). These five-packs have been priced the same throughout the entire pandemic so far and regularly come back in stock. DSG also allows for back orders. I’m sure a little bit of searching will show other retailers with similar prices but I haven’t put the time in to do so.