I do cash, and cash only.
Most of those places will accept Money Orders.
I have a good deal of three of the caliber you are looking for but I'd have to charge what it would cost me to replace it.
If you are interested, I can assist you in ordering from one of my suppliers in IL, they are dealer only so it would have to be shipped to my house. I would not charge anything to do that.
G Zanders has S&B x54r for $150 per 800rd case
Albanian surplus x54r is $82.50 for a 440rd can
Romanian 7.62x39 $131.95 for a 700rd can
shipping would be added to all of those.
Karl, is that Romanian, steel or brass cased?