Hello John,
I'd love to help you on your search for the right car rental! Which companies have you looked at so far? Every car rental company in Ireland will have the mandatory CDW (Collision Damage Waiver), and it reduces your personal financial responsibility for damage to your vehicle. The cost of CDW can greatly vary between different car rental companies, so make sure to get in touch with them to find out about the daily rate. You can find more information, and a complete overview of all tourist board approved rental companies on the
Car Rental Council of Ireland page.
Another tip that might be useful, is to ask the car rental company of your choice about the Excess Insurance/Super Damage Waiver. This insurance is not via a third party, but the car rental company itself, and it will result in a lower or no hold on your credit card at all. And last but not least, there is another helpful thread called '
Rental Car Requirements' which I think might come in handy.
Hope this helps, and let me know if you have any questions! :)