All new purchases sent to the Vault will be subject to Delaware's 0% sales tax rate whether you buy it from eBay, Alt, etc. So send it directly to the Vault and enjoy the benefits of a no sales tax state without living in one.
If you'd like to ship your eBay purchases directly to the Vault, you can do so by inputting your unique Vault address during checkout or adding the address to your account.
You can find this information by clicking the icon in the top right corner of the page. Click "Account," then select the "Account info" tab, and you should see your Vault address.
You can still ship cards to your home address and upload them to your portfolio by either card name or cert number if graded by PSA, BGS.