[soulfuldog]

I don't think the Kobo Mini is any better than your other options, I think the screen quality is probably quite similar, but it is a smaller screen. The only thing it has going for it over the others you are looking at, is that as its a little newer, so should be a bit quicker, and the battery might last better. I do agree with issybird though, going from an H2O to the Mini isn't ideal, you'd really notice the difference in size of the screen. I'd give you it for £10, but its only a stop-gap, and I think the suggestion of reading on your phone while saving and waiting for something newer is a better option.

I wouldn't be looking at anything as old as the Kobo Touch, Nook ST, probably better looking to see if you can pick up the original Kobo Aura second hand, which you can probably do for £40-60. Oh and I would definitely ignore a cheap Kindle Fire, or any other tablet.