Make sure it is in excellent condition - there are tons of excellent rearsenalled condition Mosins all over, so don't let a gunshop/pawnshop sell you a hacked out POS for $100, when Century has like new for less.
I have one Mosin right now, an M38, and had two 91.30s that I was forced to sell, and they are great fun rifles! the Polish ammo is the bee knees right now, with 440 rounds from J&G being less than $50 shipped.
Be warned, inexpensive rifles that work well, look great, and good cheap ammo spell one thing...addiction...you will want more....
www.russian-mosin-nagant-.../index.php Go here for LOTS more good Mosin info - don't ask how to Bubba it there, though - that is highly frowned on. Tons of good info.