For the past few weeks I've been visiting my local flea market and found a great little series of cars for 15mm modern/sci-fi gaming. This isn't all of them, just my last purchase, about 2,5€ in total.
I think they are made up of two series, the first beeing from Kinder eggs and the second from micromachines smart cars. I've put a 15mm beastman and a 28mm Alkemy figure at the back.
When I next play Gruntz I'll try to include them so that one can better see them.