Well, my first keyboard was a Yamaha DGX 205, its about $300. Its 76 keys with a beautiful sounds. I now have a Roland Fantom X 8, but I still use it to practise on and for sampling. I sample more off that keyboard than I do any other.
Check out some of the Casios too...a good one will be about the same price. Even some of the cheaper Casios have good organ, ele piano, and piano sounds.