Do any of my fedi friends (in Canada!!!) know a good place to shop for laptop batteries?

I inherited my Oma's Lenovo T420s and its battery is at 75% health and only lasts about 2 hours even in performance mode.

Edit:
So far my options are
1) eBay
2) Canada Computers
3) Newegg
4) laptopparts.ca
5) trying to find an original (through Lenovo's website?)