You can run Oracle on AWS in a subscription based licensing model using Oracle RDS. This is for Oracle Standard Edition One and not Oracle Standard or Enterprise Editions.
From the licensing and pricing document from Oracle (http://www.oracle.com/us/corporate/pricing/cloud-licensing-070579.pdf):
Standard Edition and Standard Edition One -
EC2 instances with 4
or less virtual cores are counted as 1 socket, which is considered equivalent
to a processor license. For EC2 instances with more than 4 virtual cores, every
4 virtual cores used (rounded up to the closest multiple of 4) equate to a
licensing requirement of 1 socket. This means that running on m1.small, m1.medium, m1.large and m1.xlarge will all cost the same from an Oracle perspective. Details are: "When licensing Oracle programs with Standard Edition One or Standard Edition in the product name, the pricing is based on the size of the EC2 instances. EC2 instances with 4 or less virtual cores are counted as 1 socket, which is considered equivalent to a processor license. For EC2 instances with more than 4 virtual cores, every 4 virtual cores used (rounded up to the closest multiple of 4) equate to a licensing requirement of 1 socket. "The big difference between SE and EE are the number of sockets you can run on (and features/options that Oracle has turned on). This is not an issue with RDS instance types as the largest instance type has 8 virtual cores. This number of core is in line with the number of sockets (2 sockets) that is allowed for Oracle SE One(the license included option) per Oracle AWS licensing terms.
