I have been using the SwiftKey keyboard app on my Android tablet for a while but unlike a PC there are no Alt codes for things like the euro symbol. A bit of Googling found the answer - install say the Spanish language to the keyboard and then all those foreign symbols and letters become easily available. For example press and hold the £ symbol and you can then choose the € instead if you want. It is the same for other letters such as é - just press and hold. To add a language go to the list of apps (not the one in settings) and tap on the SwiftKey symbol then tap on Languages and then select the language. It isn't perfect - this thread title should have capitals at the start of each word but when I add them they dissappear when I post it - but that might be a forum software glitch.