You would be surprised how wonderful a movie can sound out of a quality pair of stereo speakers.
You're asking for lack of quality in both sound and build by paying under 400 dollars for 8 speakers + the subwoofer. I mean honestly - do you think that a magician can just make this system for you and still make it anywhere decent and only charge you 400 bones?
Your best bet is to just add on to your system as time goes by. Get the amp and the stereo speakers now, and enjoy your movies like that. I promise you, you'll be able to. Then, if you MUST go for surround sound, then get your two back speakers, and then your center. Then finish it off with a nice, quality subwoofer.
I've been down this road before, at an earlier age, and would not recommend it. Low-quality high-fidelity equipment is easily prone to malfunctioning, not to mention the obvious lack in any aspect of the actual PERFORMANCE of the speakers.
Home theater, just like a stereo rig, is an investment. Make it count.