I am not aware of being charged for eBucks BUT, if you are charged it will probably just be your annual account fee (if there is one).
If you do get a card, ask for a cheque card & not a debit card. You earn quite a bit more eBucks that way & you don't need to put a pin in every time you swipe it.
With a cheque account at FNB you would get free ebucks linkage.
If you get a credit card at fnb and you want to earn ebucks when swiping your credit card then you need to link your credit card with ebucks and pay the annual fee which is close to R200