I paid $100 for my SKS in the early '90s, it's well worth that.
$500 territory is a no-go, however.
Realistically, I'd like to have an original (or close) K98 or M48 8mm Mauser and perhaps a 6.5 x 55 Swedish Mauser.
Unrealistically, I'd like to have a M14/.308 or a very well sorted M76/8mm, but both are expensive luxuries in this economy...
Mauser Werke, Schmidt-Rubin, Remington, Colt, H&K, Weatherby, Browning, Ruger, Marlin, Mossberg, Saiga, S&W, Sig Sauer....a few friends of mine