I bought the 2000 star wars system years ago at the full price of $200. I gotta admit though, I found it to be more fun than the wii,ps3, or 3ds that I currently have. Games are extremely cheap for it and pretty easy to find, coupled with the fact that CFW allowed me to play import games that would have never made it here like my all time favourite gundam VS series.
Have you considered picking one up used?
If you plan on legitimately purchasing games off the psn though, I recommend just waiting for a PS Vita price drop or some kind of price error to happen. You know its bound to happen. That or picking it up used. I'm pretty sure at this point they won't reduce the MSRP of the PSP, and are probably going to stop manufacturing them soon. I don't see them at certain big box retail stores in my neighbourhood anymore. If anything, they will be clearing them out like the tons of gamecubes walmart was clearing out a years back.
The selection of games on it are amazing and fun to play, Sony just couldn't market anything for shit during its life cycle.