If you are getting 20% of what you sell, you do not have a good business model for ebay

 I have been selling here for a decade, and I consistently take home 75%+ of my selling price.

Through listing specials and free listings, I am able to easily list about 1,000 items a month, so my lisitng fees are essentially zero.

I pay eBay 10% of the selling price, and payPal 2.9% of the selling price. Through intelligent shipping charges and shipping discounts, I essentially break even on shipping and supplies.

Other than the occasional occasional return or refund due to error, the only thing left is my cost of goods sold which has nothing to do with eBay.