Both my keys' plastic housing broke over time. After layers of glue, I gave up trying to repair them. I bought a blank key with the plastic housing attached, on eBay but found no one in Canada would cut it for me. The dealer wanted approx $180 for a new key. I got the name of the dealer below, from this forum, sent my blank to him and purchased a second key from him as well. All in (incl shipping), I paid Approx $80 for 2 keys. I re-used the electronic components from my old keys.
Sewell Lexus
Ryan Van Winkle
6421 Lemmon Ave
Dallas, TX 78209
The cost for cutting is only $10 per key, plus shipping to get the key back to you. All that they require is a copy of some kind of proof of ownership (make sure the VIN is clear and easy to read) and a photo ID. Also, include a note with a return address and let them know exactly what kind of service they are doing for you.