In case of Ireland, we recommend you to pay directly at tollgates surrounding the price of 2 EUR per paid section. There is no possibility of paying by credit card, so have your cash prepared.
There is also an option to pay with on-board unit, but this is beneficial for frequent visitants only.
All toll roads in Ireland, with the exception of the M50 in Dublin, use barrier operated toll plazas. You are obliged to pay by cash at manual lanes with attendant or at automatic coin machines.
M50 toll payment could be done online on eflow.ie, calling 0818 50 10 50 / +353 1 461 0122 to pay by credit card, or Paying in Payzone branded outlets nationwide.
If you want to see all fees of motorway network, please visit the following website where you can also find the way to purchase the electronic toll tag, if you are interested.