Full Length Car Ramps

only cheaper if you do not need a car hauler
but i see how there could be some braces in the way

still, no point in reinventing the wheel, a lot of times you can can repurpose stuff for cheaper/less trouble then starting from scratch
(of course, not always)

rip a few boards out of these and yer done (until the wife sees the boards, and decides you should build a new deck)

Flat bed trailer