I'm not in the US. Over here, the idea of a car worth driving costing only 100 euros is ludicrous, and was so even before the local scrappage schemes took plenty of 10-years-or-older cars off the road.
(100 euro cars used to be found; people who don't want to admit their car's worth nothing. They were often bought by teenagers, driven psychotically for a night, and burnt out. These days I assume they're being driven into the ground instead.)
A car that cheap here isn't expected to last long, either, but some of them do. You might have a door wired shut, the windows may not work, the air conditioning, if the car had any to begin with, doesn't work, and it might be loud. But it's a car, and they're near-essential in the USA, thanks to our lousy transportation and sprawl-encouraging policies.
(100 euro cars used to be found; people who don't want to admit their car's worth nothing. They were often bought by teenagers, driven psychotically for a night, and burnt out. These days I assume they're being driven into the ground instead.)