Since the release of the SQL Server 2014 earlier this year, lots of people have been asking if people can download the full version of SQL Server 2014. SQL Server 2014 full version is not available for FREE. You have to either get standard version or enterprise version. You can download SQL Server 2014 trial version and use it till it expire.
If you want SQL Server 2014 for development purpose or for test system, you do not have to buy standard or enterprise version. You can just download it the development version. The development version costs USD 59.95 and it is available on DVD and immediate download.
Reference: Pinal Dave (http://blog.SQLAuthority.com)