The M91/30's are what you can find in the $100+ dollar range. (after shipping, TICS, etc).
Look for one with all matching numbers (bolt & receiver). The hexagonal shaped receivers were manufacutured up until sometime in the '30's, I forget the exact year. They are a little less common than the round receivers of which all WWII manufacture are. Worth an extra $10? That's all up to you.
There are also M38's (not very common) and M44's (common but hard to get now at a decent price).
There are also Finnish Mosins which cost several times more than Russians.
I'd say get one of the latest batches of M91/30's - that's the most common - and pay no more that $150 after tax, tics, etc. Make sure it comes with the bayonet. You'll need that for proper shooting.
They were all rearsenaled after WWII and are like new. Tons of fun.