This is something that is totally overlooked, in my experience, with SQL Server 2008 R2 and SQL Server 2012. On the contrary to what happens with SQL Server 2008, the Standard version of SQL Server 2008R2 & SQL Server 2012 supports backup compression:
SQL Server 2008 R2 BOL
SQL Server 2012 BOL
http://msdn.microsoft.com/en-us/library/cc645993(v=sql.105).aspx
http://msdn.microsoft.com/en-us/library/cc645993(v=sql.110).aspx
Unfortunately a bug in the documentation said the opposite in the past, but it has been fixed quite a long ago now:
Just keep it mind