No matter what the deal, I think you should cancel all remaining contracts and exclude their monetary value from the sale. These people did not sign contracts to study under you (I'm not making any statements about your ability, so don't take this as an insult), they signed contracts with the current owner/instructor. I don't agree with contracts, anyway, and I don't think it would be fair to hold someone under contract in this situation. If you want to run a real dojo, get rid of the contracts and the store and stop charging so damn much ($150 per month--come on!). That's just my opinion--I run my dojo to train good martial artists and to improve my own skills, not to make a ton of money. Don't we have enough McDojos already?
James Huss, Suenaka Zenzan Dojo