In rec.autos.tech, on Thu, 9 May 2019 09:41:37 -0700, The Real Bev
You can get remotes for most cars quite cheaply, designed for specific
cars. They even look like the original.
You can also get directions for most cars, but probably not all, on how
to program them yourself. Just google, fob installation instructions.
I forget the url but one or two guys have instructions for most cars.
And when you buy the remote it will either have instructions or give you
the url. Put your make model and year of your car into Ebay and it will
tell you if the product is meant to work with your car.
Key blanks too can be bought cheaply for most cars.
So I have 4 sets of keys and remotes for my Toyota and I also did for
the Chrysler Sebring I had for 2 months. 2005 and 2004.
OTOH, if you want to have these cheap ones around just in case and you
don't know what car they're mant for, they might work