Then I went on amazon - the only sheets that were on prime with a good rating were $60 sets of... dubious quality, and half the ratings seemed like they were fake (almost all "recent" reviews were 1 stars). I ended up finding a (much more expensive) specialized sheet co, but am waiting 2 weeks for the delivery (4 day delivery cost $30!!).
It really kind of sucks, because I used to rely on Amazon for this sort of stuff - I WANT to buy stuff on Prime but I might as well be shopping at a street market half the time.