thanks god,i never sell anything on ebay

can someone tell me why it can happen?if we sell item on ebay,why we dont get 100% funds? sell $100 only get $86 ?
I think they are just set a fee for a maintenance of the site or they use the fee to stay remain legit of the site.. But the fee is very high..
Its better to use bitcoin for the transaction than using ebay service if you want to sell your products its better to use escrow and give a fee for your deals..