If all photography were all the same, it would make sense to just shop for the cheapest price. But photography isn't like the latest electronic gadget that comes with a warranty. In fact most photographers don't guarantee their work or their products.
All photography and photographers are different. Sure the cheapest may temporarily fill the need required but ultimately you may just be wasting money on something that doesn't do the best it can at accomplishing what is needed.
With photography (Just like hair salons or dining out) price ranges are dramatic and so are the delivered experiences, quality and satisfaction. If the photography is important (such as a once-in-a-lifetime event, or when you need a photo to convey a specific message or feeling) then price becomes secondary and it becomes critical to hire the best professional you can.
Shopping for a price is only a starting point to the real conversation about what you really need and what you want the photos to truly communicate. Although top-quality photography services may look expensive at first, in the long run the upfront cost will be minimal and the long-term satisfaction will be priceless.
To insure no regrets with your photography experience, base your decision on the quality, reputation and proven track record of your photographer independent of the price.
The most expensive photography you will ever buy will be the cheapest.