How much did you pay for Oracle? Is it a one time payment or annual?
The support contract costs more than the "license" if my memory serves me, but its very expensive. If you're doing anything remotely complicated, using their advanced tools beyond a basic RDBMS (replication, clustering, etc.) then you need that support contract.
I heard that a year or two after I left the company got an Oracle Audit and ended up paying a huge penalty.