Never trust the diagnosis of the seller.
Not knowing any of the story on that bike but judging solely by the photo...it's going to need a full set of carb rebuild kits, new plugs, fluid changeout, a seat, a battery (just guessing), fuel lines and filter(s), and a thorough cleaning of the tank. The chain and tires are likely candidates for imediate replacement as well.
If you can hear it run enough to know that the engine is solid, and the price is cheap, and it's something you want...go for it!
Clem
