Bus to Merrion Hotel, Dublin

Hi. You need the bus 747, which goe's from Dublin airport to O'Connell Street every 15 mins. The journey takes approx 30 mins and from there, it is about a 10 min walk to your hotel. Prices are: 6 euro single, 10 euro return.
Alternatively, you can buy a Dublin pass for 26 euro, which lasts for 72 hours and gives you unlimited travel on the hop on hop off bus tour, plus a return to the airport. If you need any more information, here's the link to the Dublin bus website: http://www.dublinbus.ie/en/ Hope this helps.