Tate elaborates upon a technique where he provides a refund, and then upsells the Customer.

• Customer: Buys 17$ E-Book
• Seller: Send them a personal mail, ask for how to give them the money back. Let them know that you'll be editing the book soon, and you want them to have the most up to date version.
• Customer: Is surprised, they send you their payment information.
• Seller: Refunds their money, send them an email letting them know. Also tell them "I could've left you with the old version, but I think it'd be better if you had the most up-to-date data."
• Customer: Proceeds to be very grateful
• Time Skip (~2 Days)
• Seller: Hey man, the updated version is out. You can go grab it here. I'm releasing a product later this summer for 100$. If you're interested in both, I can give you both for 40$.

Tate guarantees that this worked for him every single time.