They are getting the shells from ebay because either the metal part of their key has broken or worn out, so the key no longer works properly. Toyota spare parts think that you can only buy a complete key which is around $450 by the time you buy the complete key, get it cut and coded into the car, but Toyota do sell just the part of the shell with the key blade in it for around the $100 mark, Toyota just don't know that they sell it like that :) If you don't have the buttons you can buy just that part of the key head, some of the keys have the transponder glued in the side of the head, others have it integrated into the remote part, if you want I can put up some pictures showing the difference. I did a pricecheck for just the remote part on a new Corolla ( they are all around the same price, there are only 2 types/ frequencys of the intergrated heads that I can think of) and that's $270 for just the part.To code these in you will need a master key though, so do you have another remote key or are you using the gray key? if you only have the gray then it gets a little more tricky.