First of all for this method you need a 10$ budget to start. If you don't have it it's possible to start with less but it's very hard.
Step one:
First of all you need a Account to sell. To find this you need to join Discord / Telegran channels with the theme Fornite Marketplace and searching for cheap and good offers. It's good to look one or two days over the market so you know what's a good and what's a bad price.
Step 2:
This step is simply buy a good Fortnite account.
Step 3:
Go on Telegram and write to @RealEasySkinCheckerBot to get the full spind from the Fortnite Account.
Step 4:
Sell the Account over the Same Servers/Groups you bought it.
(Step 5:)
You can also try sell the Accounts over TikTok becourse you will find better Costumers after time.