DDH -- I also had tingling when I was in the "cage" type of pedal. I read somewhere that you should try to keep your heel down if you have this problem. I tried it, and it worked for me.

I just switched over to clipless pedals. If the reason you are putting this off is financial (which believe me, I can relate!), then try ebay for used stuff. I have seen some really good deals. If you are patient, you might be able to pick up a good pair of used pedals for $20. Mine were $30 including shipping. I also found some shoes that were only $.99 plus shipping!! When you find shoes, though, look for some that are 1/2 to 1 size bigger than your normal shoes. You will be more comfortable.