I am not certain about making and selling projects if you buy the pattern. There are some scroll saw patterns where it expressly prohibits making and selling projects from a pattern. There are others that it is ok to do that.
One should read the "fine print" when buying a pattern as many are copyrighted. You can usually also email the owner of the pattern. Will you be caught if you violate the terms of purchase, probably not. Is it wrong, yes.
I think that the pattern designers should be compensated for their work to encourage more designs.