They're dirt cheap and the Big Three in Detroit aren't making cheap sedans anymore.
Hyundai Elantra - we have a ton on base
Most govie Hyundais I've seen around are hybrids, I think to comply with previous government initiatives/instructions/mandates to buy more fuel-efficient vehicles. It is a bone of contention with some where I work too for good reason but as AA75 pointed out, cheap domestic sedans aren't much of a thing anymore.