A bit more info is needed before any one can recommend a ski for you,
How old are you?
How much do you weigh?
How tall are you?
Do you prefer jumps to rails?
If you prefer jumps, how big and what level are you at?
If you prefer rails, do you like a soft buttery ski or something a little stiffer?
Those bits of info would help people recommend the best ski for your needs.
Also you said you want to spend $400 , but do you want a ski from this season, or would you be happy with an older model.
Give this info you will get some good ski recommendations, hopefully.