I took a trip from London to Dublin on June 30 on RyanAir, and among the many things they were trying to sell us (to make up for the really cheap airfare) were a "pack" of e-cigs. I wanted one (interesting souvenir, I thought), but they would only take cash, and I didn't have any Euros on me. I hoped they would do the same on the way back, so made sure I had the 6 Euros, but they didn't offer it then.