The iPhone 7 and iPhone 7 Plus are still excellent mobile phones despite not being up to date, however it is common for some materials such as the battery to wear out over the years. If you are already experiencing battery problems on your iPhone 7, you will be interested to know how much it costs to repair it, or in this case, to replace it.
Battery prices at Apple
We always recommend taking the iPhone for repair to an Apple Store or authorized service center. There are unauthorized alternatives where prices can be much lower, but not only could it cause problems in the starting device as they are unauthorized parts, but also in the long run you could see how the wear is much higher than the original ones.

Regardless of whether it is an iPhone 7 or iPhone 7 Plus, you will have to pay 55 euros at Apple if you want a battery replacement. At this price you will have to add 12.10 euros of shipping costs in case you can not go to a physical store and have to pick it up at your home and then forward it to you.
There are circumstances in which this repair can be free, such as having additional insurance from Apple Care or Apple Care +. This type of insurance provides the advantage of finding cheaper repairs in many cases and in the case of batteries it is done without any cost. They will not even charge you 12.10 euros for shipping costs, since this amount is also covered by this guarantee.
Estimated waiting time
Generally this is a question that even the company itself does not usually answer, because it largely depends on the volume of repairs that the Apple Store has at that time. Generally, by going in person, you can have the iPhone ready that same day, about 2 or 3 hours after it is left in the technical service.
The waiting time will increase if you are going to send it by courier instead of going to the store. In that case, you will not only depend on the workload of the technical service, but you will also have to add the time it takes to send the package with your device to Apple and the time it takes to get back once it is repaired. It is usually sent with urgent parcels, but if there is a holiday in between or your address is in the Canary Islands or the Balearic Islands, it could be increased.
Can you change the battery yourself?
It is usually not advisable to repair any component of an iPhone if you do not have the knowledge to do so. In addition to that you could damage a component if you do it as inexperienced, you should know that any warranty with Apple is lost if it is detected that the device has been opened. The Cupertino company, like many others, has tools to know if a device has been manipulated or not once they have it in the technical service themselves.
However, if you think you have knowledge for it and decide to do it, there are guides that teach you how to repair these batteries and these can be cheaper. But again you should bear in mind that if the parts are not original you could have a problem for the correct operation of the device.