Yesterday, Apple apologized for secretly slowing down older iPhones in order to extend battery life. The apology was accompanied by the offer of cheaper battery replacements carried out by Apple. Instead of $79, a replacement will cost $29 from late January right through to the end of December 2018.

The battery replacement discount will be welcomed by everyone who owns an iPhone 6, 6s, SE, and iPhone 7. However, if you still use an older iPhone, you're out of luck with Apple as they are not extending the offer to any older models. iFixit is, though.

In response to Apple's apology and offer, iFixit went one better. Effective immediately, all of the company's DIY battery install kits for iPhones have been reduced to match Apple's $29 price. You will have to install the battery yourself, but the kit includes everything required to do so.

The offer is better than Apple's because it starts immediately, does not require giving your phone to Apple for a replacement to be fitted, and iFixit has extended its offer to include the iPhone 4s, 5, 5s, and 5c.

For your $29, iFixit includes a brand new replacement battery, a Kit Bit Driver, the appropriate screwdriver bits (Pentalobe, Philips, and Tri-point), a spudger, suction handle, tweezers, adhesive strips, and an opening tool/pick. The installations are also supported by online step-by-step replacement guides and tutorial videos like the one included above.

Regardless of which offer you take up, both Apple and iFixit are demonstrating just how much profit there is in battery replacements.