There is a difference between USGI pricing and aftermarket pricing. Questions to ask. Are the Marstar 5/20 mags USGI or are they aftermarket? Probably the latter. Also good to keep in mind that there are now new USGI magazines being manufactured. Can't remember the name of the company off the top of my head (thinking CMI (Check Mate Ind)) but the contract has been renewed by the US govt so these are coming available again. Original manufacture mags still pull a premium but I've noticed the prices coming down a little at the gun shows. They were over $60 each a year or so ago, I saw them this past weekend for $35 (and they were real. I checked.)