Bought a 4 pack set about five years ago. I use them at least once a month to move cars around at three different storage sites. I can even move my 19 foot 40 Buick with ease. Yes, they are expensive, but I've never had any trouble with them and they save me a lot of time and effort. That makes them worth it to me.
I will say, however, that Gary is right about two cheaper units and a floor jack for your situation. I did that for a year before purchasing the Gojaks. Too much work for me and my situation.