Hong Kong Electronics Compatibility

I am starting a round the world trip in a couple of months time. My first stop will be Hong Kong. I am thinking of taking advantage of their lower prices and buying a Game Boy Advance SP while I’m there.
I know that the games are not regionally coded so any game from anywhere in the world will work with it (although correct me on this if I’m wrong). However, will I be able to charge the thing (with or without a plug converter) in Australia, North America, UK and Europe?
Ive just been looking on the internet and noticed that on some web pages they are offering 110v and 220v versions. Whats the difference
Any info greatly appreciated