Well, we all know that bottled water is possibly the most overpriced good ever at £3.40 per litre. Let's compare this to petrol, at an average price of £1.12 per litre.
What do you have to do to get petrol, well. First you need to find an oil-containing region, then you need to drill in several sites to find the actual reserve itself. You need either an oil drill, nodding donkey or oil rig depending on the location and depth of the reserve and keep this supplied in a remote part of the world (millions of £ already) to actually get the crude oil. You then need to remove any naturally-occuring impurities in the crude oil eg. sulfur compounds, before loading it onto an oil tanker and shipping it halfway around the earth to somewhere where you can refine it. Here, you can get your petrol and many other compounds besides, but you may also want to treat it or grade it to make it better for use in cars. Also, a little-known fact is that petrol compounds are deliberately varied by oil companies throughout the year to provide the best performance. Once its been refined, you then need to ship the petrol to a petrol station where it can be consumed. This is in addition to the millions of safety laws and pieces of legislation that the oil company will have to adhere to in every country in which it operates.
Whereas for water, you extract it from a spring in the uk somewhere. The spring is unlikely to be deep or hard to find so this will be very easy. You then purify it and optionally add some other materials. You then bottle it, write some bs to put on the label and ship it to supermarket distribution centres.
Which is bloody harder?