A standard cheap twin size flat sheet at Walmart is $4. I can make 5 decorator throw pillows with one sheet, including the ruffles. I was looking through Pottery Barn one day and saw this scrumptious bed of white ruffles and lace. For less than $10, I was able to duplicate the look.
I can make a twin size duvet cover with two sheets, two full size sheets for a full size duvet cover...etc.
and I can make a ruffly shower curtain with one sheet.
The possibilities are endless. I've made slipcovers for chairs, and summer skirts, all with sheets. I know of clothing designers who will use sheets for their mock ups, rather than spend money on the expensive fabric until they get it right.
If you don't think you have the money to decorate. Take another look at the sheets. And save the high thread count for sleeping on.