You need to say "sold" on the No4.
M95 carbines in 8x56R ("S" marked on the receiver) seem to go for $100-$150, and rifles for $125-$175. As for the M95 in 8x50R, as usual, JP is correct, and while $100 more seems a bit high, it's sure in the ballpark. The real find in a M95 variant is the M95M or M95/24 in 8mm Mauser. Un-sporterized (and with intact extractor, which commonly breaks), they are even less common (in Canada anyways), as they were "shootable", being in a readily available round, and were fodder for sporterization.
8x50R ammo is scarce and collectible, and even 8x56R ammo, once seen regularly at gun shows, is getting that way. A bunch of guys shoot the 8x56R, but I don't know anyone who shoots the 8x50. The issue with 8x50R will not be the brass (you can use the readily available Graf 8x56R), it's the dies. Lee sells the 8x56R Hungarian dies, but not 8x50R, so you're looking at US$100+ for dies. You need a clip to shoot the gun and they are easy to find. If you shoot without one it's single shot, but please carefully place the round under the extractor as it would go if taken from a clip, then close the bolt. If you drop the round into the chamber, then drive the bolt home, the extractor has to jump over the rim. After a while the extractor will break if you do that.
http://home.att.net/~vintage-gunlore/8x50r.htm
I have a rifle in 8x50R but haven't shot it yet. I haven't looked into it, but I suspect you might be able to trim about 1/4" from the bottom of a 8x56R die and use it for the 8x50R, although it would probably reduce the body too much and might have to be opened up a bit for the last 1/4". Or if you could get some brass already formed in 8x50R, any "fat" 8mm die could be used for neck-sizing, e.g. 8x50R Lebel, 325 WSM.