Ah. Last shop in Dublin (and the island as far as I know) closed at least 25 years ago. Was across from the General Post Office. Forget about coins while you are there, as I dont think you will find any unless things have changed. Instead just enjoy the culture. Some awesome museums, and of course Guiness (my cousin works for them). Its a great town, but I am biased....
Well I already have the Jameson distillery on the list. I might as well add the Guiness tour as well.