some models gives more option then others. look for the reliability and workability. im not very familiar with model since mine is old.

I use a nice and not to simple Maudio MK461C :P 61 key, as for a 25 key? i'd say dont bother, go big bro!

well I can't afford a bigger one and it has to be very mobile^^

Check out these -- I like M-Audio. They're cheap but still really good quality, which = WIN in my book.

http://www.musiciansfriend.com/prod.....ler?sku=706313

http://www.musiciansfriend.com/prod.....ler?sku=703611

I also really trust musiciansfriend.com. Do some searching around there and I'm sure you'll find something cool. =) good luck!!

definitely second the op for musiciansfriend.com

Yeah, Maudio is my teeny USB one. It's good.

I would recommend any that's cheap. Generally a USB one will be sufficient and can be found at any up-to-date music store. If you want to get some tasty, get the keyboard and go to a proper music store where they'll sell you a 'blue box' along with Reason 2.0.

However, that's all I can recommend really if you want ze cheap.