Before we begin, let's be absolutely clear that there's no single answer to this question. For one thing, different companies and different industries all require different kinds of websites. If your business needs custom web applications, advanced e-commerce features, tons of online video, or other time-intensive features, you're going to end up spending more than a small start up that needs none of these things.
But with that being said, we'd like to point out that more often than not, it's going to be a significant investment. That is, business owners tend to hurt themselves by spending less than they should on a commercial website.
You might think that answer isn't surprising, given that we design websites for a living. But, if you ask anyone who's familiar with web design, they’ll probably give you a similar answer. The reason why it comes down to simple math: even if you're running a very small company, the chances are good you’re hoping to attract at least 100 visitors per day. Now, it's entirely possible that you are aiming for 10 times that, or a hundred; but for the sake of argument, let's say that you're looking at 100 people per day.
If you take the time to think that through, you'll quickly realize that your website should be seen at least 35,000 times a year. Many of those visitors won't be people who can drive by and see you in person, and even if they could, they're likely to come to your new business website at least as often.
That makes your website an incredibly powerful marketing and public relations tool. It's going to be the first thing a lot of new potential customers see, the place where other potential customers go when they've been recommended to you, and the first stop for colleagues, journalists, and other interested parties who are researching your company. We wouldn't go as far as calling it the most important business decision you will make all year, but it's probably in the top five.
Remember that as you look through bids for your next business website. Spending more doesn't always mean getting more, but there's a strong correlation between high-quality, maximum effectiveness, and professional rates. It's always tempting to save a little here and there, but don't forget about the tens of thousands of people who will see your site this year.