My brother-in-law was told he had a "Missing" AC, and was quoted $700 for his Honda Prelude.
Turns out the clutch for the AC fell off, a common problem apparently in some older preludes and civics. However, the mechanic said the entire compressor would have to be replaced for $700 because you just can't get a clutch by itself, even though I found it online for about $125, and I found a DIY on how to install it

.
So, go ahead and pop that good ole panel off that is under the front passenger wheel to gain a better view of your AC compressor, because it can't really be missing considering the drive belt is hooked to it...but who knows maybe your clutch just fell off also...