You do know that Visa/Masterdard and the rest charge the merchant a percentage of every purchase? WHen you go to the store and buy a CD or groceries or whatever, and charge it, the store pays the Visa people somewhere between a half a percent and 2.5 percent.
It might occur to the store to add that percentage to any sale put on a charge card - just as it occurred to you - and it in fact did occur to them. But it is against the law for them to do that. It is probably against the law for you to do that as well.
It is possible ebay scratched your sales because the offer was illegal with that condition.
It is no secret paypal charges a percentage to commercial customers. Visa charges the seller, and they charge you too if you don't pay off each month. Banks charge for each check, or they require a minimum balance for "free" checking so they have your money to use for free in the mean time. Money orders cost extra to buy. And my back charges to cash money orders form out of the country. No one processes money transactions for nothing.
Paypal makes it easy for my customers in Australia, Poland, the UK, or wherever to pay me in US funds without jumping through hoops.
On the other hand I have never used ebay, so I cannot report.