Very wise Mikey P take a look at this
http://www.amazon.co.uk/Bushcraft-Inspirational-Survival-Wilderness-Signed/dp/0340834838/sr=1-1/qid=1170817805/ref=sr_1_1/203-4064485-6393549?ie=UTF8&s=books
and I think there are more for around the £90 mark
£250 quid for signed copy
I've got a signed copy (signed by RM and Ben McNutt who did the illustrations and am not really bothered if it's signed or not and am more interested in the content, but having said that I wouldn't sell it because it's pretty dog-eared now and have no intention at all of selling it.
I'm not really interested in autographs but if I had Elvis or Muhammed Ali autographs for example, I'd sell them for the higest price I could get my meat hooks on and buy a Tappi tent