Cheapest fix would be a gasket set and a carb kit. Carbs aren't all that complicated, you just have watch closely as you take it apart, watch for springs n' stuff . Don't force anything apart and don't force anything back together. Carb kits usually have a blow up diagram of the parts too. If you want to keep the cost down I would go that route. You can always buy new parts if it doesn't work so youv'e really got nothing to loose by givin' it a shot.