100 bucks a mo buys you catastrophic coverage with ~2K deductible (My own catastrophic plan was 96/mo 1500 deductible, 25 year old non smoker).
Catastrophic plans ARE NOT universally creditable for preexisting condition:
http://www.washington.edu/admin/hr/benefits/insure/other-hlth.html
Also generally you're not eligible for catastrophic coverage if you have AIDS, diabetes and other such conditions.
I would do more research before you start making naive assumptions about the real world. When I left a full time position for Grad school (say laid off for sake of the argument), my COBRA was around $380/mo. Had i had diabetes or something like that I would have NO real option to insure myself on a realistic budget.