It takes about $100k to get a cubesat into orbit, plus costs for building the sat itself (custom fabricating a miniaturized drive plus a suite of sensors).

So not much, but the larger problem is we don't know how this drive works. Miniaturizing it could impact performance, as could other electronics in the satellite... given the unknowns it makes sense to let NASA do some more terrestrial due-diligence before going to space.