We just did this. We rented from Avis at the airport, drove to Galway, and circled our way back to Dublin. 7 days total, with every extra coverage available, came in just under $900. We are happy with our choice to rent, and would have done so even if it was much more expensive. We were able to modify our plans on the fly depending on weather, how tired or hungry we were, seeing something not planned, etc. One good example is Blarney Castle. I had not even looked into it because I had no desire to kiss the stone. Then, our guide at Ross Castle said we would probably really enjoy the gardens. Since we were on our own, it was easy to add that on our way to our next destination. And, yes, he was right!

The motto was - get up and out every morning - beat the tour busses to the bigger attractions.