Very few Haynes manuals ever go out of print, so in theory none should ever be hard to get, technical book shops should always be able to get them, but yeah from England is always going to be a lot cheaper, simply because it was a much more common car over there.
As to my ebay search, I just typed in "micra manual", and yeah as above $35 delivered is easy enough, I waited a few days watching two because I noticed the UK sellers randomly price matching/undercutting each other, and got one for under $30AU shipped. ($27 I think)