how much do you have to pay for battery service

iPhone Battery Replacement:

Current Apple Prices:

• No charge for in-warranty or AppleCare+ plan.

Out of Warranty Prices:

• iPhone X or newer: $69 U.S. Dollars.
• Older models: $49 U.S. Dollars.

➢ Check AppleCare Coverage.

Click ▶︎ iPhone Battery Replacement.

In warranty, nothing unless the battery is above 80% capacity. Out of warranty, for an iPhone 8 Plus, $49.

I see that you have iOS 16 beta, which is only available legitimately to developers and by invitation to seed participants. If you are not a developer I would strongly suggest reverting to iOS 15, as you have a “bootleg” version and do not have a certified or approved version, which might contain spyware.

Depends on your location (country really), model of iPhone, and whether it may need additional repairs. There are certain conditions where Apple or an Apple Authorized Service Provider may refuse to perform a battery replacement service without addressing another issue (such as a broken screen assembly). If there's liquid damage, they may refuse to perform any kind of repair service. Also it may matter if you've had aftermarket service (such as a screen replacement). Also, Apple Authorized Service Providers often match Apple's prices, but they are free to set their own service prices.

If you choose mail-in service, that will require a shipping fee that includes both the outbound box and shipping back to you.