Where can one find the 'furrin made'? I might as well get the best "bang" for my buck. :)
You can try AIM surplus, J&G, Sales MidwayUSA, CMP (if you are active, guard, reserve or retired - they have a killer deal on Greek 30-06)) or Shotgun news. Check with your local gunsmith, there a lot of garage operations.
Cheaper than dirt, Cabellas and other often have milsurp at slightly higher cost, but in smaller lots (not everyone buys for a group at 1000s of rounds at a time). Prior to purchase, check ammo forums for bad ammo lots - for example Indian ammo from up to the late 70s and early 80s was supervised by the Brit military - by the late 80 it was all 'home grown' and mostly junk. Same same for some old ComBlock arsenals. When in doubt, check with someone you know locally and trust - the advice you get on the web is worth exactly what you pay for it : )