If I bring an MP3 player I presume I just use the exact same lead which I've connect to my home speaker system?
Not really, home audio systems generally use L+R phono connectors. Professional audio speakers take 1 of 3 types of connectors which are either a) speakons b) XLR or c) 1/4" jack.
So it depends on the speakers you get. Your mp3 player will have 1/8" headphone connector out, so you need to get from this to the speakers.
DJ speakers or "tops" come in 2 types, active and passive. If they're passive, you'll need an amp to drive them, so you'll connect your mp3 player into the amp and control the sound level from the amp, if theyre active you can plug straight into the speakers.
When youre sourcing the speakers ask what type (active/passive) the tops are and what connectors you'll need to get from an mp3 player to them.
You can usually pick up a brass (recommended) 1/8" to a 1/4" adaptor for 3-4e and then 10m Jack or XLR cable for about 10-12euro. So you shouldnt be talking any more then 25-30e for leads. Find out the above anyway, foreign holidays are becoming more and more popular and bringing the mp3 player is as well. Hotels should be used to those requests, so if they put you on to someone get them to tell you what you need to bring if anything. Post back here for for more info if required.
btw, Ask are there poles as well, raised speakers at head level have a much greater "throw" on them, ie, the levels travel clearer for further then if they were sitting on the ground playing to 20 peoples legs.
I'd be surprised if you paid any more then 80-100 euro but Im only familiar with Irish prices, last thing, pro tops are very heavy, so dont contemplate bringing with you.
To go from mp3 player to XLR use a [broken link removed] with a [broken link removed] cable, you'll then need to go from that cable to the speakers, 2 x 5m XLRs should suffice