It is quite common myth that SQL Server 2008 Developer Edition is FREE.
SQL Server 2008 developer edition has same code base and same features which are available in SQL Server 2008 enterprise edition. Only difference between them is licensing terms. Developer Edition can not be used in production environment and it can be used on development server only.
I have received quite a lots of emails how this can be downloaded for free. First of this version is not free. It is available for $50 to download. However, those developer who are really looking for free edition of SQL Server 2008 should try SQL Server Express Edition.
Reference : Pinal Dave (https://blog.sqlauthority.com)