Try
www.planecheck.com for prices - typically 20,000 to 25,000 Euros for an airworthy one by the looks of things.
I believe the engine TBO is 1,800hrs or 12 years, whichever is the sooner, although you could run it 'on condition' with a Private CofA as I understand it.
Make sure all mods have been done and that there aren't any expensive 'lifed' components coming up for renewal.
So . . .engine needs money, airframe needs money. I'd get a good aircraft engineer (not associated with the A/C) to go over it for realistic costings.
Good luck - I'm sure there are other more knowledgeable folk on here who can give you more info.