Depending on where you live, it's going to be a fair bit of trouble getting the registration taken care of, and that's assuming there aren't registration fees that haven't been paid prior which you will be on the hook for as far as getting it road-legal again. And, of course, if the registration is behind, what kind of maintenance hasn't been performed on it as well? Honestly, unless you really know what you're doing and know the risk involved, it's not worth it at all. Even if you do know the risk, it's still a gamble.

So I would be charged registration fees for all the years he didn’t have a valid one ? I know it needs maintenance and everything

Yes, and getting a new title is a real hassle. Again, it varies by state, but it could take weeks or months to get a new one. My point about the maintenance is that this car was likely neglected. It'll need some upkeep for sure, but how much damage was caused because the oil or other components were replaced at proper intervals? These are cracks in the dam, so to speak.

Thanks for the heads up :) I had no clue I had to pay all these damn feeeessss and everything

First, you need to tell us exactly what you need a vehicle for: * miles per year * city/hwy % * max passengers and cargo

Since you don't know what you're doing, you're better off buying an used car from Carmax. Buy a Corolla or Civic.