Good Morning, How and where do I get replacement batteries for my Toyota Prius key?

I replaced my battery last week, Inver Grove Toyota have free battery check and in my case the reading showed that my battery is reading low and needs to be replaced, especially before winter, so I did replace it with them, cost was about 130$ for my Camry. so I recommend you stop by them and check on it.

I've never had to replace my key battery even after 3 years. But, open it up, see what's needed and go to Ace Hardware. Or call IG Toyota and ask them. You can try Batteries Plus too for a replacement battery. But first I'd call the Dealer and ask to talk with someone in the Service Department.