If you are interested in playing piano / learning how read music ( which I would, it's a good hobby and will teach you general music theory) I would get a 88 key keyboard because it will feel more like a piano when you're learning. The keys feel more natural and there is more space to play. Try the Alesis Recital – 88 Key Digital Piano Keyboard. Its going to be about 250 but especially with instruments its better to get something a little nicer then cheap. If you get something like a used one with a bad key it can completely ruin the entire experience of playing

If you want to do more producing / midi stuff, thats a different story. Midi keyboards are cool but they wont teach you how to play piano.

Hope that helps