If you're getting something to learn how to play the piano (which is what I'm hearing from your post), then I suggest getting decent touch-sensitivity above any other features. Also, for actually learning to play, you'll want 61-keys or more; the full piano is 88 keys but may be out of your price range.
I don't have a keyboard in that price range to recommend for you -- my advice is to go to a music store that sells pianos and ask a sales rep how much bang you'll get for your buck. I just bought a piano, and we got a better deal instore than we found online, as the instore package came with a bench, pedal set, and two extra pedals at no extra cost.