Battery service at CA$35 may be limited to one repair per iPhone. After December 31, 2018, the fee will change to CA$65 for all these products except iPhone X, which will change to CA$89. Issues caused by accidental damage aren't covered under the Apple Limited Warranty.
Your iPhone service might be covered by warranty, consumer law, or AppleCare+.
This iPhone 6 Replacement Battery is what you need to bring that dead iPhone back to life. Grab the Fix Kit for everything you need to do the swap.
If your Apple phone is experiencing battery issues, you might be eligible for a battery replacement.