If you really don't want to go spend the money on a real cover.. make one. I did!
I bought a fabric from wal mart and sewed it together. it cost me around $15-20. Its super easy. If you can't sew.. find someone (bribe them
) to sew it for you. I made mine and one for my roomate in less than an hour.
**All you have to do is measue your comforter, get enough fabric for 2 sheet like pieces (get them about a 1/4 yard bigger than you need), put them print side in.. sew 3 of the edges together, put the comforter in, sew the last edge..
PRESTO! 
**
Mine was cheap and sort of cheesey, but it has lasted me 2 years of college thus far!
ETA Because I have a typing problem