I have somone interested in my car, he's had RAC report done, driven etc and is keen. But I'm yet to see a deposit and he's sent me a 'letter of offer' to buy the car, but saying this is subject to finance within 21 days. Does this mean if I accept his offer I can't sell my car to anyone else until the 21 days are up? His letter below:

The reason why i am offering $37,000 instead of your asking price of $38,000 is because both of the rear tyres need to be replaced and i am deducting your share of the RAC inspection report (to follow). I have based the replacement cost of the tyres off a quote from Bob-Jane for a pair of 245/45/r18 bridgestone tyres, for which i was quoted $405 each. The RAC report cost $295, which means your share is 145. That comes to just over 37k.

This offer is made subject to me being able to obatain finance within 21 days of the offer being accepted you.

let me know what you think