A question on Synthesizers

[Exodus]

I would stick to Yamaha. I've used many keyboards, from cheap up to quality ones. I prefer Yamaha in the price range you mentioned. You can get this keyboard for a reasonable price. You get touch response keys, which is a "must have" feature for a piano player. You get a great amount of voices and styles, some of them are shitty as hell, but Yamaha's Grand Piano sounds just amazing. You may get this one too, does it's job, but don't expect miracles.

You can also try Roland, sometimes used ones are sold for a fair price and they are far more better than the new, cheap versions. Avoid Casio at all cost. With daily use, the keys will deteriorate, and won't be so good to touch or use at all. Not talking about the sound. Casio offers a great amount of styles and voices which worse than the sound of a jewerly box.

All in all, for that amount of cash get a used Roland or a Yamaha. Nord is a different level, but if you get your hands on one, stick to it. And if in the near future you plan to get another gift for them, add this to your shopping cart, as it really gives a thrust to the volume. Good for personal use, you can connect a simple jack to it and get loud at house parties. But adding to the piano really makes a difference compared to a 2.5 watt speaker, they usually have.