Oh hun, you shoul dnever pay that much for wrapping paper. What I do is either go to a Dollar store, or wait until after a holiday, and you KNOW everything is on sale then...and i buy 3-4 rolls of whatever looks nice. I use it for tablecloths, presents, confetti...whatever i need it for...
anyway, your idea of scaps is a good one, but that is going to probably be a lot of pillow cases, and before you know it, you will be spending money on more fabric/pillowcases!
sorry, didnt want to dampen your spirits, but I am just saying...