The ribbon cable connector used for floppy disk drives on PCs can be used as a GPIO connector.
They are larger than than the Pi GPIO connector (34 vs 26 pins) so they overlap some. These are cheap (free if you have old PCs to scavenge from.) One problem - they won't fit in a case made for the Pi, but I have used them in cases that I built that held the Pi as well as other hardware. If you do use this cheapskate trick, I recommend trimming the unused lines from the ribbon cable to prevent confusion. It is also a good idea to plug the unused holes on the connector so that you don't accidentally plug it in wrong.