There's probably little in the way of commerce laws re magazines except for those state/cities with bans on later manufacture mags.
By the way, at the last gun show I bought a large box of new/like new USGI mags from a dealer for $3 each. About 3 out of almost 100 I bought had notable wear, the others were nearly new if not unused.
Be careful buying mags wholesale. They may not be price competitive.