I am a luddite when it comes to technology. So I apologise in advance.

I am having a party in my flat. I don't know the best way to (cheaply & simply - is that even possible?) get music to all of the flat.

I used to have 3 ipods, with the same play list, we would start them at the same time and put one on each floor in their own speakers. All ipods have come to unfortunate endings.

I don't think I can use a wifi system as there is a 500mm thick steel transfer plate between floors 1&2 which makes even cell phone reception dubious on the bottom floor. (but are there super duper wifi systems nowadays?) Floor 3 is the roof so outdoors but there is a plug.

I don't really want to buy 3 more ipods.

I was wondering:
1) can I use my itunes music on other mp3 players ? (these are cheaper right?)
2) is there a more logical way that any of you tech genius' can think of to do this? (without wiring a sound system through the flat).
3) where would you recomend I go to buy whatever it is I go buy? Wan chai Computer centre? Sham shui po?

Thanks a million!