How much to fix the vapor recovery system in a 05 Chevy colorado?

I want to buy a 05 chevy colorado from a private party but they say that it shows an error that "something is wrong with the vapor recovery system". Could this be a serious, expensive problem? Or is it nothing to worry about? Also this truck's inspection has been expired for months, how is the process of bringing it up to date?|||No, it's not a big deal really. It could be something as simple as the gas cap defective or even not tightened enough. A gas cap needs to be tightened to where you hear 3 clicks. All the system involves is a charcoal canister under the hood with a return line coming from the gas tank to that canister and another line leading up to the intake to burn off any gasoline fumes, more or less|||The vapor recovery is part of your emissions system, if your state has emissions testing your vehicle will fail. You could throw parts at it or take it in and get a proper diagnosis it's your money.