I haven't played one. From specs and other info:
It cost around $200, new, in 2010.
Guitar Center has a used one for sale for $100:
http://www.guitarcenter.com/Used/Casio/WK200-76-Key-Keyboard-Workstation-111798799.gcSo the price is OK.
The keyboard action is "synth-style" (spring-loaded), not "weighted action" (what an acoustic piano uses).
Assuming you're on a _really_ tight budget:
. . . it has 76 touch-sensitive keys, and a bunch of voices (including piano).
That's enough, as a "first keyboard", for you to learn some music and keyboard skills. You could make decent music on it. There are better keyboards, but they'll be more expensive.
Worst case, you'll either give up keyboard study (and sell it for what you paid), or get enthusiastic and buy something better (and sell it for what you paid, or keep it for trips to the beach).
You will need a stand. I have a "double-braced X-stand" which is pretty solid. The single-braced X-stands aren't as solid, but they might do OK with the WK-200.
You'll also want a pedal -- the M-Audio SP-2 is around $20, new. There are cheaper alternatives.
Have fun --