Well for AR mags - mako still has them in stock for a decent price. They are steel and not aluminum. Here is a link M16/AR15 Steel 30 rd 5.56x45mm Magazine - White Follower
and if IIRC if you are a member at arfcom you can use the code ARFCOM at checkout and get 5% off the order if over $100. Plus you can use the code FREE-GRND for free shipping. From what I understand you can use both together for more savings.
Also cdnn has some of the fn 30 rd. steel AR mags (made in Belgium) still in stock for $29.99.