I bought mine from another site about 8 months ago for 82 dollars. I would highly suggest buying either a miniSD card or a micro sd card with a mini sd card adapter. Also be sure to find an adapter for either card for your computer and install linux onto it, after flashing your dingux. Depending on how computer literate you are, you can do this yourself or find someone you know that can help you. What you're looking for is called Dingux:
http://dingoowiki.com/index.php?title=Dingux:About http://www.dingoo-scene.com/TheCompleteidiotsGuidetoDinguxWindoze contain great information for how to install dingux. From there you should have a ton of free ware games that come with linux. You also get the option to play games like Doom (the main reason I got the dingoo) or Quake if you get the necessary WAD files. Of course it also comes with way more emulation software than there was on the native firmware. The main problem with this dingux install is that it doesn't include a TV out option that the dingux does. There is less documentation to do this, but here is where you can install the work-around:
https://github.com/uli/dingoo-tvoutEven if you cannot get dingux to work (it took me a good while to get everything sorted out.) the native firmware comes with NES, SNES (though SNES is kind of slow), Sega Genesis (also doesn't work too well, dingux has better emulators for Genesis and SNES), CPS 1 and 2, Neo Geo, and GBA (GBA is the best one.)
Other than that its a basic media player, so I'd say it was worth the investment. It doesn't feel too cheap, although I notice that the screen gets dirty underneath (I took it apart once to attempt to clean it and it was a pain to get opened.) But since I use TV out quite often the screens not a huge concern. The radio barely works, but it plays mp3's and videos quite well.