You cannot use an Amazon gift card balance to buy other third-party gift cards.
No, you buy eBay gift cards on Amazon . Amazon does not list eBay gift cards for sale because eBay is a direct competitor. While Amazon sells "Specialty Gift Cards" for many other retailers (like Apple, Starbucks, or DoorDash), eBay is notably absent from their catalog. 🚫 Restricted Payment Policies can i buy ebay gift cards on amazon
If you find a listing for an eBay gift card on Amazon from a third-party seller, be extremely cautious. Even if you could find one: You cannot use an Amazon gift card balance