Without doing your research, it's going to be difficult to cull out the ones that may be worth it, from the ones that are not. As far as condition, a lot of them can look "mint" on the outside because they've all been refurbished. The chance of getting one with a bore that is truly "mint", is pretty slim, however. Be aware that a lot of dealers, who just don't know any better, or who are trying to hype them up, will describe them as mint or "unissued" when, in fact, they could have been through at least two wars and then simply refinished. The Soviets didn't typically change the barrels during their postwar refurbishment programs, so that's something to keep in mind.
If you're just looking for a shooter, follow the EE here, other trader boards and/or auctions and other sources for something that has a good bore and is priced a little lower. Until you learn more about what makes a 91/30 worth $175 or more, you're in somewhat dangerous waters. But, if you have the option to pick through a crate, this improves your odds and is something that not everybody has the opportunity to do. So, the devil is in the details and a little education on them can go a long way. Check out www.mosinnagant.net and www.7.62x54r.net to get some more info on what to look for.
Now, having said all that, I've been known to walk into a shop and pay more than average market value for something that really jumped out at me, or "called to me". I wouldn't fault a guy for that.