For me, a $10K emergency fund is enough to buy 2 or 3 cars... but I'm unlikely to need to spend it on any because my wife and I own two cars but only use one, and keep the other as a backup (and also for occasional hauling, as it's a truck).

I haven't done the math to find out if the overhead (taxes and insurance) is higher with two $3,000 - $5,000 cars than with one $10,000 car, but I like the versatility and redundancy.