i ended up buying a used PSP from craigslist for $50 a few years ago. the seller never specified that the wifi wasn't working and i didn't know i would have to worry about it not working. i sent it to this awesome trustworthy guy on a different psp forum and he fixed it (or replaced the wifi board) free of charge.
but i honestly never used the wifi on it except the internet browser or the streaming video player. i kinda wish there was wireless play involving monster hunter and phantasy star without being adhoc (although i know xkailink has supported this, just never bothered)