Supposedly that type of failure isn't the gear itself, it's the transmission shaft that the gear rides on.
If that's the case, it'd probably cost well over $1000 if you rolled the bike into a shop. Maybe $300 in parts and a few weekends work if you do it yourself. That's if you can resist the urge to do anything else while you're in there.
If it's really the gears or something on the kickstarter shaft, it's an easy afternoon fix for maybe $100 in parts.
IMO not even close to being worth it unless you want a project.