i got my C&R about a year and a half ago. since then, i've accumulated 11 C&R approved rifles. i have a russian M44 carbine on the way to my house now. it was a whopping $50. you can get these surplus rifles for next to nothing, and they are a lot of fun to shoot. the kick is almost like firing a shoulder mounted artillery piece, and you can't two finger the bolt, you've got to muscle it.
while most of them are well used, expect many of them to look pretty rough. if you find a super nice one, you'll pay a premium. i have a K31 that looks like someone used the buttstock as a shovel, but it shoots like nobody's business. if you get lucky on these, there's usually a surprise under the butt plate. the tag identifying the soldier to whom the rifle was issued will still be under there. there are several stories of K31 owners finding and corresponding with the soldiers who were issued them. most of the french rifles are in like new condition and unfired, so those are always good deals.
just be aware of the 1903s prior to 1918. the receivers are prone to exploding. watch for last ditch WWII japanese rifles. these are fine to collect, but are too much of a hazard for the range.
once you get your C&R, send or fax it to SOG, AIM, and Century and they will send out quarterly flyers with their rifles and prices listed. the average price of a C&R surplus rifle is about $100.
if you also get into them, you'll find a lot of rifles not on the C&R list that are fun. i have a romanian AK47 and an FAL made from south african parts. they're great shooters too. you can get the M1 garand from CMP without a C&R license (a definite must have rifle). i would say they also have 1903s, but those are about gone. watch the flyers. they'll tell you when shipments are getting low. i got a springfield 1903A3 right before CMP ran out. now the prices are significantly higher than what i paid. i also managed to get an australian lithgow from the last imported batch. you've got to be quick.