like the otehr guys said, your compressor will shit its pants if you try to run it horizontally.
something you could do is make a shroud.
mount the cheap unit inside the apartment ie take out or simple open the window, mount the aircon inside on a bracket or sit it on a box (anything, just to hold it in position) and then use thick plastic sheet/concretors plastic/ply to make a shroud, the purpose of which is to funnel ALL of the hot air from the back of the aircon into the outside air
youll also have to run a hose from the drain to the outside, otherwise itll drip inside your unit, wetting your pile of messy dvds and making a dripping noise
have fun