I got
Price Tapestry the other day to have a play around with whilst I had a bit of spare time on my hands. I managed to create
Compare Vitamin Prices Online in the space of abount 15 minutes.
Sadly as with all price comparison engines, you are forced to either edit or rely on datafeeds which to me, has always been, and will continue to be a PITA. Once merchant may call the tablets "Glucosamine yet" another merchant will call it "Glucosamine 500mg" and therefore a comparison engine will show 2 different products.
Its great for small niche comparisons such as TV's, Sat Nav systems, where there's a specific manufacturer, make and model number.
As for price, I got it last week for £75 from memory, so keep checking
Price Tapestry for what seems to be daily price changes.