If your on a tight budget. Rotax may not be your best choice.. That great deal will cost $1000 plus for a rebuild. I own a Rotax and love it. Im just speaking from the truth.
You should look into a different class. Maybe Briggs 206 or KT 100. Karting cost money and you often have to chase down problems, parts, new tires, race fuel, cost to get to track, cost to enter race, ect. It never ends the costs!!!
If you want to stay in karting at an affordable price. Tag/Rotax class isn’t the way to go.