>>106557484
aliexpress batteries are around ~$15.
If you want to do it properly you also need back plate adhesive precut film and battery stripes, both at couple of bucks.
Need to heat up the back, I just use hair dryer then pry one corner with sucker and split the rest with old credit card.
Next if battery has stripes just remove them, if not heat up battery with hairdryer and gently pry out, some people wetting the area with alcohol but I never tried then. Clean residue install new battery adhesive stripes, install adhesive film carefully position backplate.
Watch out not to touch camera lenses with bare hands, best is to get sheet of camera protection adhesive from aliexpress also couple of bucks. All the repair shops tend to smear shit over camera lenses with their dirty fingers idk why they do that. They're very hard to clean but it's doable.