I got mine in the same condition that yours is in. The carbs were the main problem I had with getting it back on the road. They're easy to take apart and clean, its just adjusting them properly and keeping them clean was a pain in the bottom. As far as the dollar amount invested for its return to roadworthyness, I'd say it was about $200-300 tops. Of course that included a new tire ($100) and having the fork seals replaced by a shop (another $70...a stupid design prevented me from getting the fork apart myself
) If there's even the slightest amount of rust in the gas tank then one of your first steps should be to clean and seal the tank. If not you'll be cleaning the carbs until the end of time. Trust me on this.