Welcome to all you new, young collectors. I hang out on a number of boards, but you have discovered already THE go-to board for cool C&R guns. This is a big site and has a little of everything.
Several of the boards here, the Collectors Mosin and Enfield off the top of my head, are probably THE best boards for those arms anywhere...
Tuco was right when he recommended a Finn M39 as a good one for a new collector. They have good sights and tend to shoot very well and can still be bought pretty cheaply for what you get. The Finns tweaked the triggers, mags, and stocks of the Mosin design and installed heavier barrels to make them better shooters. Nice rifles. BUT, they have gone up in the past few years so get 'em while you can.
Some other bargains out there for guys getting started, in no particular order:
(These are also what I am into lately because even though I'm an older guy, cost is still a factor for us old married dudes!)
1. Swiss K31. Like the M39 Mosin these suckers SHOOT and have good sights and usually very nice, crisp triggers that make you look good on the range. A buddy of mine who is very much into competitive high power shooting has pretty much eschewed all other C&R rifles for K31s. The Swiss made a very nice bolt rifle. Get some of the primo Swiss GP 11 ammo while you can.
2. Lee Enfields. These are great guns with tons of history and character behind them and can still be had for good prices. Cheap surplus ammo is pretty much gone, but if you handload they can still be enjoyed and made to sing.
3. Mausers. The Turks have already been mentioned, but this is a huge field and the Mauser is just the Big Kahuna of military bolt guns. Endless variations and they can still be found for reasonable coin if you're careful. They tend to be well made, rugged and almost bullet proof. Kinda like the Mosins. Russian Capture K98s are a good way to get into a German Mauser with war history without breaking the bank. All original K98s are rapidly becoming thousand dollar and UP guns.
4. Mosins. Still cheap for common varieties, tons of variations and history. Built like a Mack truck and built to last. See comments above for Mausers on ruggedness.
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The US stuff like M1s and 03s are nice, and a real weakness of mine. They also tend to run at least 500 bucks a copy and UP, way up, for good ones. A service grade M1 from CMP is usually a wise investment and much cheaper than buying one at a show. CMP is pretty good about making things right if you get a bad one or a broken part. If you're a young American guy, your Dad or Grandfather probably carried or used an M1 either in war or peacetime and that's a great connection to them and the Greatest Generation.
Plus, they're cool to fondle while watching Saving Private Ryan or Band of Brothers.
The German stuff can get pricey really quick. Ah, the allure of being bad and the "cool" guns and equipment of the bad guys always go for bucks. Original condition German is NOT cheap and can be tough for a young collector to break into. Plus they're faked like no tomorrow to make common examples all matching, prettier, or more "rare." Caveat emptor ; be careful on those.
The Japanese stuff is still under-appreciated and under-valued in my humble opinion and might be fertile ground for a young collector. The Japanese board here is primo and a good place to learn about them. Check it out.
Hope you enjoyed these random thoughts on collecting and remember to have fun with it. You don't have to spend a ton of money to enjoy this hobby. Get something you like, and some ammo for it, and get out and burn powder with it. That's a big part of the fun. CMP sponsored matches are a great way to get into some shooting, meet some great people and generally have a ball. Researching the guns and their history here and other places on the net is FREE, and that's a big part of the fun factor, too.