First time in Ireland, how do I purchase gifts, etc and find room to get them home? Can I ship them from Ireland back to the US?
A lot of places, like the Waterford factory, will ship things for you. I believe Avoca Handweavers and Blarney Woollen Mills stores will also ship.
We had an expandable suitcase that allowed for some, we carried the hide-away tote carried here at RS ($15.96 today) and checked 2 bags (on an American carrier) and also planned for extra stuff in the carry-on. Oh, shipping is fairly easy but not cheap and not usually quick which puts a dent in the gift giving when you get home.
I usually pack a large back pack in my suit case; so that I can pack my dirty laundry in same & leave space in my suit case for my goodies. You only want to take one suit case and one carry on w/you.
I used to be that only Waterford, Bellek, Blarny Woollen would ship your gifts home, however, most irish shops will mail your gifts back home; which is fantastic because you are not lugging your gifts all over the place & you dont have to worry about breaking any glass or pottery.
Depending on how much you want to take home, it might be cheaper to pay for an extra checked bag. Check with your airline for their extra per-bag charge. It's often upward of $60-$80 USD, but that gives you 50lbs of "express" shipping that would otherwise cost much more to get home. Just be ready to declare and insure the bag for anything fragile like glassware.
Be aware that the UK is now fanatical about carry on baggage, limiting you to one item only, no exceptions. Ladies your purse counts as an item so be sure there's room for in your carry on. Some airports are also serious about the size of your carry on bag and make you "test fit" it in a bin before you can even go through security. Guess they're expecting you to load up at duty free shops on the other side of the security checkpoint and want to make sure there's plenty of room in the overhead bins for all that liquor :)