Microsoft has announced that it will begin charging for Bing Search API access. The company started offering the services on a subscription model and will starts at roughly at $40 for up to 20,000 queries. Bing Search API 2.0 will be free during a transition period which last several months. The subscriptions will be offered through the Windows Azure Marketplace, where developers have a choice to try the new version of the API for free right now.
Details regarding the transition timeline, pricing structure, and other changes will be announced in upcoming weeks. In the meantime, we encourage you to explore the Windows Azure Marketplace and read the documentation on accessing data sets and APIs. As a Bing Search API developer, you can expect the transition to involve targeting a new API end point, moderate changes to the request and response schemas, and a new security requirement to authenticate your application key. Developers using approximately 3 to 4 million queries and above can expect to transition through a separate process (details will be provided shortly).