Service grade M1s were $730 from the CMP earlier this year when they've had them, and those are the cheapest you are likely to find. I'd expect more in the $1000-$1200 range at a shop, quite possibly more than that.
If you find one at $700 the seller is either lying, doesn't know what they have, or are trying to save their kneecaps from a loanshark.
I think I saw M44s in the classifieds recently (maybe still there are) for under $500, or at least in the ballpark.
I've been K98 hunting for a bit (just looking for a shooter RC) and I think I've settled on Gunbroker being the only viable avenue, although I haven't gone to Pack and Postal. I was the high bidder on a K98 auction that ended last night until 30 mins before closing where it jumped another $170, which I expected to happen anyway. I didn't up my bid. Just gotta be patient I guess...
good luck