I bought a decent older M77 with a tang safety about a year and half ago and paid $150 for it. 308 Win, no rings or scope. Shot great - nice old gun. Condition is everything of course. The one I bought had it's share of dings and scratches like you would expect an older gun to have that was actually carried and shot and didn't just sit in a rack collecting dust.
Check the usual sources - blue book of gun values, Gun Broker, Guns America and you can get a feel for asking prices. Asking and getting are two very different things so closed sales results are far more meaningful than asking prices.