No I agree with Sagan Darkside on the price of RP books, on the hours I spend reading them, re-reading them, and the inspiration they give to my games I would say they are very good value for money.
The problem is they need to be, as I can continue to run my D&D without buying a single other product for the rest of my life. If something is more expensive then I'm less likely to buy it even if its really a bargin for what I'm paying for since I always have the option of spending no money and still getting a similar enjoyable experience in my D&D game.
Up to about a £10 I might impluse buy while in the shop.
£10 to £15 I might impluse buy if it covers a topic I need resources for say a monster book, or city setting when I need one.
More than £20 I need to have heard good reviews, and still think about it for a while.
£30 quid or more I'll wait for a Birthday or Christmas or Lottery win, unless it is absolutely fantastic.