Dropshipping, where you fulfill orders directly from a wholesale supplier, is allowed on eBay. Remember that if you use dropshipping, you’re still responsible for the safe delivery of the item within the time frame stated in your listing and for the buyer’s overall satisfaction with their purchase.
However, listing an item on eBay and then purchasing the item from another retailer or marketplace that ships directly to your customer is not allowed on eBay.
Activity on eBay is required to follow this policy, the eBay User Agreement and all applicable laws, as well as respect the rights of third parties. If it doesn’t, eBay may take action consistent with applicable laws and the eBay User Agreement, and may even be legally required to do so. Such actions may include, as an example only: Removing the listing or other content, issuing a warning, restricting activity or account suspension.