I buy/acquire many 3rd gen mags at gunshows. The 9mm and 40S&W mags are for pistols I have and/or going to have. I also pick up 45ACP mags for people I know that are seeking 45 mags. I have no intention of getting a 45 pistol as I am not a fan of 45ACP.
2-6rd for 4513TSW
1-7rd for 457/4516/4513TSW
1-7rd for M945PC
4-8rd for 4506

I sell them for $5 over what I paid + postage.
The past couple months I sold(to around the country) 9 10mm mags for $45 each +postage. My 10mm mag supplier has dried up(for now).