I bought my wine in Karwigs in carrigaline on a sale or return basis. They also delivered and collected the leftovers for free. They also offered a lot of advice about wine.
Please note I have no connection with Karwig Wines, just a satisfied customer.
Also I noticed in the Irish Times last week, they had an offer for a return trip from Rosslare to Cherbourg with Celtic link ferries for €150 for a car and 2 passengers. Good table wine is available in wholesalers near Cherbourg for between €3 and €4 a bottle.