My last invoice, per eBay's calculations: 13.31% of the total sales/shipping dollars. Plus 30cents+3% per transaction for PayPal. On my lower dollar transactions, that formula often hits 7-8-9-10% total for the transaction. So 20% is not far off for lower dollar transactions. Even for larger dollar transactions 16-17% is not far off.

Selling on this board saves at least 10+%, more if you ask for no PayPal or Buyer to pay the fees. And you deal with an overall friendlier group of buyers.
It's like eBay in the old days 15 years ago when I first started selling a few goodies.

Also, here you can post one scan of many chips as a contact sheet, takes about 1/10th the time of setting up separate eBay auctions, even for very similar items where you only have to change the name and the title.