Taking the Airlink Express (Dublin airport bus) is the cheapest way (7 Euros) to get to Dublin’s city center from the airport.
When I’m not flying in the premium seats, lounge access can still be available to anyone with Priority Pass. My home base is LAX so whenever I’m traveling internationally through LAX’s TBIT, I get to use the Korean Airlines (KAL) lounge.
Priority Pass: Get access to airport lounges with many different credit cards. These credit cards will typically have an annual free, but some will have no annual fee for the first year. Having access to a lounge before a flight makes the stress of travel much more relaxing.