Transponder key fob died.
 

My RX-8 came with the type of key fob that's the size of a credit card that you don't need to insert a key. The device has stopped working and the dealer is telling me that it would cost $500 to replace. Has anyone else had this problem and is there a cheaper solution?:scratchhe

Do an advanced search on 2006 keyless entry.

you can buy them on ebay, just make sure the seller allows returns since not all key fobs work on all models.
you can also program the fob yourself if you have one working key.

if you find a local mechanic with the device to program the keys he would probably charge you a heck of a lot less then 500


so there are options.