Erm well
a) You won't sell it for £80, but you knew that.
b) Chips are still expensive, £30-40 - I did my executor3 years ago and still have my xbox being used as a media center. The best thing you can do really, or
c) Softmod it, but I don't know how easy or reliable that is, you'd need to get hold of a few things first that would probs cost around £20 posted anyway.
You could also, strip the case out and fit a proper pc in there as I once did, but then got very bored of that project and left it.