[2WD_2016]

I'm new to this keyless setup and the Info here has helped with my concerns, thank you.
Next I'd like to purchase a spare fob and key (making 3). The dealer quoted me maybe $500 for the setup and fob/key.
I see the hardware at under $200 doing a search, but it must be cloned and the key cut.
Any ideas on locksmith cost to look for, as well as device cost range that's better priced, seeing this may sit in a lock box all its life as a spare? I'm assuming removing the battery won't erase the programming and it'll work again with the battery reinstalled?
Thank you.