Just work the action, check the bore to make sure it is nice. Many will have been counterbored to remove a rough patch at the end of the barrel (this is caused by soldiers not using the cleaning rod with the centering cup thingy (IDK what it is called) properly), counterbored rifles work just as well as nonconterbored rifles withou the messed of bore. Then enjoy it. (after a nice night of cleaning cosmiline off of it, and re-oiling it.
$90 is about the regular price for one. Also, Tula is more collectable then Izhevsk (tula generally has a arrow in a star for the logo) and hex recievers are more collectable then round recievers. Guns made before 1941 tend to have a better finish, but they all function the same. (Also, Finnish is more collectible then Soviet)
Check out this site for more info. http://7.62x54r.net/
Here are some of the markings a Mosin can have. http://7.62x54r.net/MosinID/MosinMarks.htm