There are a lot of people asking if it is legal to buy Fortnite accounts. The answer is maybe. Let’s take a look at the terms of service for buying an account:
You may only purchase, sell, or re-sell an account through the Epic Games store if you are the original owner of the account and you have not violated any of our Terms of Service. If we determine that you have illegally purchased, sold, or re-sold an account, we will terminate your access to the Epic Games store and your account. You may not purchase, sell, or re-sell accounts that were created through illegitimate means (i.e., stolen credit card information). Accounts that are found to have been purchased through illegitimate means will be permanently banned from accessing Fortnite.