Is replacing the battery free?

For rather limited reasons such as a fault or early depletion (less than 80% battery health with fewer than 500 cycles) under warranty or AppleCare. Maybe if it swells during the warranty period, although that would typically damage it to the point where it would require a replacement.

Maybe if there's a battery replacement program.

Other than that, no. Apple charges for battery replacements in most cases.

Hey there,

yes if your iPhone In-warranty or with AppleCare+ For more info See ☞ iPhone Battery Replacement - Official Apple Support

Twinzmom69 wrote:

Is replacing the battery free?

Only if the device is under warranty and only if the battery is determined to be defective. In other words you cannot simply walk into an Apple store and demand your battery be replaced because you want it replaced. In most cases there is a charge for replacing a battery that has reached the end of its useful life. Apple’s “Battery Health” feature will alert the user when battery service is recommended. The typical charge for replacing an iPhone battery is $49.00 to $69.00 depending on the model.