for a keyboard: for less than $200 you should be able to get a late 80, early 90s synth. look for something from yamaha, roland, ensoniq, korg or one of the casio cz series. look for something with touch sensitive keys, if it has aftertouch then even better.
here some free samples. you'll probably find out pretty quickly that doing your own sampling gives you better samples than anything you d.load.
http://machines.hyperreal.org/winky/0022.html?Winky