Wow, very broad question. You can start by checking here:
Parallax's C&R Forums Lots to choose from, but that's a good thing, no?
Might also want to look into applying for a Curio & Relics Federal Firearms License so you can have these rifles sent directly to your home. It pays itself off after one or two purchases.
If you want to stick to the same caliber, go for the Finn M39. It's one of the best Mosin Nagants, IMHO, and you can find one in great condition for about two bills here:
www.gunsnammo.com. There's lots of surplus 7.62x54R ammo available, plus Wolf ain't too expensive for new ammo, either.
Mausers are also great. There are about a billion different kinds of Mausers, but one of the better buys right now is the Yugo M48 8mm Mauser. You can get one in pretty darn good shape for about a bill, plus there's lots of surplus 8mm ammo out there for cheap (mostly corrosive, though, so clean accordingly). For a little more money, German, Persian, and Swedish Mausers are pretty sweet.
www.empirearms.com has a great selection of Mausers.
Lee-Enfields are a bit more mainly because there's very little .303 surplus ammo left. You can find good examples of the rifle right now for about $150 at
www.aimsurplus.com or
www.jgsales.com. You're prolly stuck w/ new production ammo, though. I've had good results with PMP (available at
www.centuryarms.com).
Everyone has their favorites, of course, but they're all pretty strong, reliable, and accurate designs. The condition of the rifle itself will probably be more important. Good luck!