A Poor Collector's Guide to Buying Great Art by Erling Kagge
Many of here at Fount spend money on peculiar things. This often leads to empty pocketbooks and the neverending desire for nice things.
This book by Erling Kagge is a essential toolkit to buying art, understanding value, and how to amass an art collection that is respectable, yet frugal. Buy this book for the cheapskate in your life you could use a better taste in art.