> Online, especially for non-physical items are tending to have fluctuating prices, trying to find the ideal price to maximise profits.

Unfortunately, yep.

Like you, if I ever buy anything online such as a flight, I will check every possible site and pick the lowest, clearing my cookies all along the way to ensure that they aren't messing around with it.

I really wish they didn't do that! I'd love to see a study on this behaviour's effect on sales though.