portable ac unit for closet grow?

I will be adding a 400W HPS to my roughly 30 square foot closet. I was looking at getting this ac unit

http://www.sears.com/shc/s/p_10153_...gle Room&psid=NEXTAG01&sid=IDx20070921x00003j

simply because keeping the doors open isnt that cool when Im trying to sleep, thought it has worked the outdoor temps will get up to 85 some days and I dont have any AC.

Is there any other solution that would cost less? and will tihs a/c do the job?
Are there units that can be moved from room to room under $150 it would be nice if I didn't have to put huge holes in the wall?

thanks to all responders

if you could somehow vent the air it will cool it and you wont need an AC. too bad you dont have an attic above your closet or cant make your own hole to vent

I have a lightbulb fixture, I wanna remove it but Im not trying to mess up the ceiling in case I sell my house