Selling process: Post the sneakers that you want to sell on your personal account and hope that people see it. You can also be the worst person on the Internet: The type that comments on big sneaker accounts to announce that you have a size available of a certain sneaker for sale.
Payment process: However you set it up: Venmo, PayPal, in person.
Pros: You make your own rules. You keep all the money from the sale.
Cons: There’s no regulation. Every sale is risky. You’re relying on your own following/word of mouth to get out that you’re selling sneakers.