Handloading is the only way to get GOOD, affordable ammunition at any kind of pricing that won't break the bank.
Remember that HALF (or more) of the cost of a cartridge is in that brass casing that you throw away. That casing, if treated properly, can actually last you 30 shots or more.
Ammunition for my Snider is $10 to $12 a shot.... if I can find it anywhere and, even then, it will be a century old and likely duds. But if you have the casings (make from 24-bore shotgun brass or plastic) and a mould, the price comes down nicely..... to 35 cents a pop. Smokeless loads for a .43 Mauser drop from $4 a shot to 20 cents if you handload.
It took me MANY years to find a single round of 6.5x58P for the original Vergueiro and I STILL would not have one were it not for this board (Thank you, DIOPTER!). But now that I have an original, I find that I can duplicate it for about 60 cents a shot.... and that is Match-grade loads which are legal for hunting. And you can do the same with almost ANY of the old military cartridges.
If you just want a bucketful of cheap, consistent, relatively short-range ammo which is not hard on the shoulder and helps your barrel to last almost FOREVER, there is the famous C. E. Harris UNIVERSAL LOAD FOR MILITARY RIFLES. It is 13 (thirteen) grains of Red Dot shotgun powder with a 180-grain (or thereabouts) CAST bullet. No filler, no wads, no nuthin': just load it and shoot it. It is low-recoil and limited-range.... but BUFFDOG uses it as his Gopher-sniping load out to 300 and TINMAN204 is getting ONE-INCH groups with it at 200. They are both on this forum: ask them. Cost? About 12 cents a shot...... and it is equally-applicable to almost ANY fullbore military cartridge of the type used in both World Wars.
If you MUST buy tons of surplus, get some brass cases and modern primers and switch the loads over to the new cases with new primers. SURPLUS ammo generally is "surplus" for a REASON and the reason generally is dodgy primers. I switched-over some utterly useless Turkish 8x57 in this manner and discovered that I had 3 WWI rifles that were shooting 1 MOA or very close to it. You might want to think about that if you buy a Moisin-Nagant or an SVT and a couple cases of ammo and find you can't hit a barn from inside: Russian primers are notorious for deteriorating.
For bulk lots of oddball brass..... and some loaded ammo..... my source is Trade-Ex Canada; their ad is up top of this page, 2 in from the left, 2 down in the block of ads under the Beaver. With that..... and a bit of work..... I can keep almost any rifle from either World War running happily..... and NOT break the bank.
Just sayin'......
