How to set up a price comparison site?

I have an idea of setting a price comparison site that compares journey times, cost and CO2 footprint across the UK using, private car, train, bus/coach, metro systems, aircraft, boat and walking/cycling. How do I go about setting something like this up with no website design knowledge whatsoever!? I thought it would be best to start off small, ie Scotland wide before branching out to the rest of the UK, Europe and maybe the world one day. Any ideas?