Legal Question in Business Law in Massachusetts

I would need more information for a complete answer, but here is a shot at it:

For purposes of illustration, if Dealer A offered Vin # Car X for $6500 as is and then you made an offer on Vin # Car X for $6500 contingent upon repair of window and bumper and you deposited in good faith $500 then:

Dealer A offered the Car for $6500

You counter offered for $6500 plus fix the window and bumper

If Dealer A then posted the SAME Car (not a similar car) for $5000 as is then they have effectively countered (and thereby rejected) your offer of $6500 with the repairs. However, if you could prove that they accepted your offer of $6500 with the fixes you could enforce the agreement. As a practical matter it is more likely you would simply go and get your deposit back and move on to another dealer or you could call them up and say, "OK I'll take the car as is for $5000 and apply my deposit" - this would be your acceptance of their counter offer.

Or you could counter again, maybe say OK I'll take it for $5000, I'll repair the window myself, but Dealer you touch up the bumper." Yet another counter offer.