I've looked over MANY different Mosin Nagants in stores that were priced anywhere from $79, to $149. You USUALLY get what you pay for. The cheaper rifles will undoubtedly have rusted out bores, much worse condition stocks, some will even be missing parts! At any price most are not good "pieces of history" as they've been reworked by importing armories (look for a shiny silver muzzle - 91/30's chopped down). The price you mention isnt likely to change anytime soon considering the 91/30 and its variants are probably the highest production bolt rifle to ever exist.
They
CAN BE great rifles! I've got an M44, and a 91/30.
Look VERY closely before you buy!!! You'll find more weird things about the gun when you get it home than you could ever imagin! I bought my 91/30 (for $99) because the action was VERY smooth (something you really need to look for as they vary GREATLY!), got it home and found out from its stampings that EVERY piece of the gun was made in a different year, plant, or even country! Bad thing is that the whole gun was in beutiful condition, UNTIL I cleaned all the grease out of the bore. It's pitted up worse than a gravel road. It'll still manage under 3" groups with the factory sights every time at 100 yards. And that's equal to my M44 that had never been fired, and has a spotless bore (unissued, excellent condition, $129)
$129 is
not an out of the ordinary price for ANY model of Mosin Nagant. You need to look over their inventory and see if those particular rifles are worth even a penny. Before you frown on the 91/30's for being as long as a telephone pole, let me say they are the best balanced rifle I've ever held in my hand! And handle BEUTIFULLY! Even better than their carbine siblings IMO.
If you pick a good one... Their SUPER fun to shoot!!!

And easily my favorite of all to take to the range for a day of GIANT muzzle flash, and loud noise fun!

Good luck! It'll put meat on the table!
Check out the web sites, you'll learn more than you ever wanted to know! Dont bother buying the book on them. I have it, everything in the book is on the web. Tom is of knowledge on these weapons as well.