Here's how one4all works.A friend used a one4all card at a retailer recently, and was charged a fee for using it - not something I'd heard of before.
10% of the gross sales price is paid in commission.
Assuming you are selling goods that have 23% vat, this is effectively a 12.3% commission on your net sales price.
They do not deviate from this commission rate except for the very large retailers where they will go as low as 2%
I put it as a marketing cost as the hope is that the customer will return, but it's debatable whether it is worth it.
On the other hand, me2you charge 2%-7.5% depending on various factors. We are at 3.5% with them. Far fairer and you will see a far bigger variety of stores on their retailer list.
Btw, credit and debit cards are well under 1%