Dumond chemicals make a great product called peel away, that I have used recently.  It is funny, because I just got a call today from a previous client that asked for a quote for removing and cleaning a paints garage floor. The stuff isn't cheap, like $200 bucks a 5 gallon, but it doEs work. just figure only half the coverage they publish, because you have to put it on really thick for good results.

2 bucks would work. I would try 2.25/SF and feel them out, just so you have a little room. just remember that you will use double the product