A skilled photographer may be able to create a much better image in 5 minutes than a less skilled photographer could create in an hour. Nevertheless, every image, every piece of art, is going to reflect the thought, time and energy that goes into it.
It's said that Leonardo da Vinci spent 4 years on the Mona Lisa. Now, I'm sure that that wasn't continuous effort. It probably sat in a corner for a while and he'd look at it and think "That fingernail could look better" and then change it. At the same time, he was a great sketcher. Are his sketches as good as his paintings? Of course not. He put much less thought, time and energy into them.
Likewise, with photography, I can crank out a quick snapshot or spend a day or more creating a single image between photography and Photoshop.
When my clients come to me and ask for a quote, the major question in my mind is "What is the proper amount of time that I should devote to each image?" What drives my decisions (and the buyer should also be thinking of this) is "What approach is likely to give the buyer the highest return on their investment?"
If a company's use of a photo is for internal use then they should probably take their own photos or buy cheap stock photos. They just need a "sketch".
But if a business wants images that will attract customers, enhance perceptions and increase sales then it's a whole different ball game. They should spend enough to ensure that their marketing materials and websites are effective. People compare websites and brochures to decide where to buy. Because we buy with our eyes, the importance of the photos can hardly be overstated.
However, you don't want to overspend on photography either, you want to maximize your return on investment.
You need to figure out:
How much profit is involved in an average sale?
How many times a year does an average buyer make a purchase?
How many years do we keep an average customer?
Multiply those three numbers together and you get the value of an average customer to your business.
With that number in mind, you can make a much more informed choice on what you should be spending to get new customers and how much you should spend on photography.
Think of it as buying a customer. If an average customer has a value of $2500 to you would you be wise or foolish to try and save money by hiring a cheap photographer? If the photos that they took brought in just one less customer a year, your savings would be more than wiped out - those photos would be costing you more in lost business the longer you used them.
Another way of looking at it is this - if you go with a cheaper photographer, the most you stand to gain is the difference in price from the better photographer. The amount you can lose from lost sales may be much greater. They may make your marketing ineffective. If you go with better photos, the most you could possibly lose is the difference in price from the cheaper photographer, but the potential upside from increased sales they bring is unlimited.
The better you understand what new customers are worth to you, the better you can communicate to your photographer how good the images need to be to accomplish your goals. Let him or her know what you're trying to accomplish with your photos. Then you'll get an estimate that better reflects the type of image you should be using.