I searched for them on Ebay an Trip-Up was only listed BIGBADTOYSTORE has them for $38.00 jawdropper: Long story short mainly looky for Big Daddy!
They weren't rare back in '90. Most of the Micromaster sets were shelfwarmers (or pegwarmers, I should say), as I recall. I would never pay $38 + shipping for a loose set. But that's just me. They're not so much "rare" as they are "scarce". Knowhutimean? I saw the hot rod set in a comics/collectibles shop MOSC selling for $45 and it made me just wish I had bought a few extra back then and kept them sealed. Mine have had much love as they combined my love of not one, not two, but three different things: Hot Wheels and Matchbox cars, vintage hot rods, and TFs. I don't care what anyone says--I love me some Micromasters, and I can't wait to get my hands on that Allspark Power Big Daddy. I never imagined such an obscure character would get something like a "Classic" treatment. I wish Hasbro would do a whole line of vintage/classic/muscle car/hot rod TF toys. I just can't get enough of 'em.