The selection is a lot more limited than when they were first offered, but these flannel sheet sets are now down to $8.99/set, even for king size.
Do check out the reviews (which are mixed) before you buy, of course. For the record: I bought a set of these when they were down to $15, and they’re fine. Not luxury bedding or anything, but nice and soft, have washed up well, etc.
For $9 you really can’t beat ’em.