£80 - 100 is a little low for a tablet and imagine you'll end up being a bit let down by anything in that price range. Have you checked out the Google Nexus 7 for a good all-rounder that is cheaper than in iPad?
Anything under £100 will probably be slow as hell. You're best of heading down to PC World or somewhere and trying them out first hand. Give them a work out, load up some videos and large images to see how they hold up.