Amazon and buy yourself another replacement and keep it on hand. I've got one sitting in my garage just daring the operating one to fail when it's 100+ outside. Make sure it's the same in terms of specifications as the one you took out.

I know firsthand of a local HVAC guy that keeps a large selection of these on his truck and brags about charging $500 on hot days to replace them. The parts are ~$20 and it takes 10 minutes tops.