I've been kicking around the idea of getting an original PSP - they do emulation to a point and with a bit of MESSING ABOUT you can run pretty much any PS1 game on them. Some going on eBay refurbed for less than £20.
If you don't mind the tinkering and aren't too fussed about having a "current gen" system, might be worth a punt? Only thing putting me off is the single analog and (I think) only 2 shoulder buttons.