The best advice is to know the services you really need, and only pay for those. The typical six-page small business Web site with a single response form, for example, can find good virtual web hosting with multiple e-mail aliases, cgi-bin access, and a T3 connection to the Internet for $18 to $25 per month (see also The Web Hosting Options). If you need SSL Security, expect to pay $35 to $75 per month. Setup fees are typically $50, though sometimes higher for special features. Prices will be higher in many localities. Large companies and high volume Web sites will pay much higher rates to get the services they need.
But I am paying too much! you cry. Find out what you need and then shop around. When you discover a better deal, see if your current ISP will match it. (Life is more competitive these days when business customers can get Web hosting any place in the country.) And when comparing Web hosting prices with your local ISP's hosting rates, remember that you'll have to pay $20 per month for access anyway, so figure that into the equation.
The most difficult thing to learn is how responsive the Web host ISP is to fixing problems which arise. How slow is the site during peak hours? Does the ISP host a very high volume site which slows everybody else down? This kind of information is difficult to find out except by asking some of the ISP's current customers.
Like much shopping, referral is often the safest. And referrals to the best ISPs is what you pay your Web site developer to give you. Select your Web site developer before you select an ISP. But if you plan to shop on your own, at least you have a list of questions to ask, which can help steer you to the best service/price ratio possible.