Hi mensanumber,
I'm a big fan of the free material that's available from
www.mba.com (the practice CATs and problems), but I have to ask WHY you'd be focused on squeezing every available question out of the software? Plenty of fantastic practice material can be found elsewhere (and at a reasonable price). I imagine that your time is valuable, so you might be better served purchasing the OG (or the supplemental books) and practicing with those, rather than retaking and retaking and retaking those practice CATs. Once you've worked through the books, I'd be happy to recommend some additional resources. If you're looking for advice on how to put together a "plan of attack" for prepping for the GMAT, then feel free to contact me directly.
GMAT assassins aren't born, they're made,
Rich