EBay charges their (usually 13.5%) fee on purchase price + shipping fee+ sales tax.
This is the industry standard, and has been since Diner's Club began operations in the mid-50s.
The fee is charged on the payment and not on how the payment is broken down.
EBay handles the payment of sales taxes for sellers in over 200 jurisdictions in the US alone, plus Canadian, Australian, UK, and EU VAT/GST assessment and forwarding.
Sellers have the OPTION to subscribe to a Store and the OPTION to choose among various levels of Store.
Stores include a set number of listings and reduced final value fees. There are a few other perks to a Store.
A Store is not worthwhile unless the seller has at least 300 different listings, until then the Free 250 Listings plus another 40-50 at 35c each is cheaper.
Store sellers also often get Free Promotions of thousands of listings. These are usually used before the set number of Store Listings.
Sellers have the OPTION to increase that fee by using Promotional Listings. This is another name for advertising.
Sellers have the OPTION to set that PL fee at any thing from 2% to 100%. EBay makes suggestions which are good for eBay, not necessarily for the seller.
