Microsoft turned some heads last month when they announced that the Bing Search API would be heading exclusively to the Windows Azure Marketplace. A lot of non-profit groups like libraries were understandably upset because Microsoft wanted $40 a month just to use the new API. After hearing the criticism from non-profit groups, Microsoft has adjusted the pricing to include a free option.

The Bing Search API is now available on the Windows Azure Marketplace. From there, you can download the API and begin using it in Azure Web apps to provide Bing-powered search results alongside images, video and all kinds of other great search-related queries. The new Bing Search API can also be configured to your liking to return only the most relevant data to your applications.

Microsoft, in a move that will make non-profits love them, are keeping the Bing Search API free up to 5,000 queries. That’s a little better than Google’s Custom Search which only allows up to 100 queries per day which equals out to about 3,000 free queries a month.

For applications that use more than 5,000 queries a month, Microsoft has an easy to understand tiered-pricing system. It goes from 10,000 queries for $20 a month to 2.5 million queries for $5,000 a month. For 2.5 million queries using Google’s Custom Search, their pricing comes out to be $12,500. Either way, Bing Search is obviously the more cost effective option. It’s worth pointing out that Google at least only charges you per 1,000 queries, up to 10,000 a day, where as Bing charges you upfront for all the queries in a month. So you can get away with paying less with Google if you have slow search days.

If you are using the Bing Search API 2.0, Microsoft encourages you to switch over to the new Windows Azure Marketplace version. You can still use the old 2.0 API for free until August 1 which is when Microsoft will switch over to only handling requests for those who are using the Windows Azure version.

To encourage people to make the switch sooner than later, Microsoft is offering a free trial for any subscription tier. You can start processing 2.5 million queries for free as soon as you sign up. If you find yourself needing even more than 2.5 million queries a month, Microsoft can hook you up for a small fee.

If all of this sounds better than you ever could have imagined, check out the migration guide (docx) for moving old Bing Search API apps to the new Bing Search API. In doing so, you’ll be signed up for the free trial. Just be sure to change back over to the free tier before the trail ends unless you can afford $5,000 a month.

As an aside, Microsoft is removing two services from the Bing Search API since they aren’t used all that much. Starting August 1, the PhoneBook SourceType and the RSS endpoint will no longer be available through the API. Microsoft’s translation service will be available only through Microsoft Translator (for a separate fee) instead of the Bing Search API as well.