In this order, I bought two packs of cheap battery:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitWKENOmjb-VYGa47fGklvyGHCvNgsQZTz-t89__ufw0-u71UTfG21GZtR02mH_VtWKIO5PMfpZhDzoCtRSsm3g7snqd1gwHdwitAoUE-rJHFDdBgQz89iUDlRMNjeUW5MU8l_S2e97p4/s320/IMG005.jpg)
They are LR44 and CR2032, and they are probably the most common models. As you could see, these are big packs and I expect that they can last for years. Given they are so cheap, it's good to keep some at home and when they're needed, I can always find them immediately.
Highly recommended.