Developer edition is free to download, and has all the bells and whistles of all the versions, so that you can develop the features you require. HOWEVER, you cannot use it for production in any way.
Below is an answer to a similar question on another forum.
As stated in this blog, SQL Server Developer Edition is for development and testing only, and not for production environments or for use with production data.
SQL Server Developer edition offers the full feature set of SQL Server Enterprise edition, when you need to develop an application that uses advanced features, for example, table partitioning and transparent database encryption, SQL Server Developer edition is useful.
In addition, for more detailed information regarding to the license issues, please call 1-800-426-9400, Monday through Friday, 6:00 A.M. to 6:00 P.M. (Pacific Time) to speak directly to a Microsoft licensing specialist. For international customers, please use the Guide to Worldwide Microsoft Licensing Sites to find contact information in your locations.