its all very well doing that mate but your local trader/garage has a thing called overheads,theres sooo much a garage can spend on before they make a profit.
look if you can't be arsed going the auctions to see have a peep in parkers or what car in newsagents as they give various prices like trade,px and private, nearly all traders laugh at them guides though as they can be well fookin out, but so can the proper trade bibles too.