You've always heard that you "get what you pay for," but that does not seem to be the case with the new cloud computing movement, specifically with Web APIs. Some of the best services out there don't need a credit card number, and I suspect that trend will continue until greater numbers of the available Web APIs have normalized. That's going to be awhile.

For example, the GeoNames Web API, from geonames.org is a geographical database that can be downloaded free of charge under a creative commons attribution license, containing over eight million geographical names and consisting of 6.3 million unique features, 2.2 million populated places, and 1.8 million alternate names.

However, if you don't want to download this data, and most of us don't, the data is accessible free of charge through a number of Web services. Geonames.org is already serving up to over 3 million web service requests per day, and all for no subscription fees. There are already over 40 mashups that leverage this API, as well as those who leverage this API for any number of enterprise or Web applications out there.

If you're looking for real estate info delivered as a service, then check out the Zillow Web API. The Zillow API Network turns sites into mini real estate portals by offering real estate content. In other words, they allow any enterprise application, portal, or mashup to leverage Zillow content and other services.

There are two types of Web APIs from Zillow. The first is the home valuation API, providing home valuation based on location. There is the search results list, Zestimate home valuations, home valuation charts, comparable houses, and market trend charts. Moreover, there is the Property Details API, or property-level data, including historical sales price and year, taxes, beds/baths, etc. Finally, you can find out who you're living near with their neighborhood demographic data.

Of course, you can't forget about the dozens of APIs provided by Google, from mapping, to finance, even including the new APIs for the new Android mobile platform. Google is slowly cornering the market on well-defined, and free, APIs. Chances are that you've leveraged several today, whether you know it or not.

How will money be made from providing APIs for free? You have to consider the fact that most of the content on the Web is free to the browser user, at least they don't pay for it. Business models are driven in other ways, such as ad revenue. In other cases, sites that offer data for free to the browsers are simply providing the data using another mechanism. Thus, there are more ways to leverage the data directly within other applications or mashups. I suspect that most of the more popular data-as-a-service APIs will remain free, or available at a very low fee. After all, while the use of Web APIs expands, the key is adoption and leveraging, and the money will come down the road for those who find their APIs pervasively embedded within enterprises or clouds, though enterprise usage fees, in essence how those creating freeware make money today.

Eventually you will see fees for information delivered via APIs that you would pay to see within a browser. Moreover, there are complex business services and data, delivered as an API, that may actually have to charge large fees right away, considering the limited audience and the costs of development and support. However, they will typically be much cheaper than having to develop those services and maintain that data yourself. I don't see many of these types of services out there now, but as the world of the non-visual Web expands, more of these will show up on the market.

Should the possibility of future fees affect your development efforts? A better question might be, how did the possibility of future fees related to expanding your business onto the Internet affect your business? Be aware of their potential, but also be aware of the benefits.