Oracle Database 11g Standard Editon One description from oracle.com portal:

$180 per user (5 user minimum)
Oracle Database 11g Standard Edition One is an affordable, full-featured database for servers with up to two sockets. It provides enterprise-class performance and security, is simple to manage, and can easily scale as demand increases. It is also upwardly compatible with other database editions and can easily grow with you, protecting your initial investment.

In a recent TPC-C benchmark test, Oracle Database Standard Edition One on HP Linux delivered a world record price/performace of $.54USD/tpmC for TPC-C Benchmarks. Now you can get the fastest performance at the lowest cost.

Benefits:

• Get started with low entry cost of $180 per user (minimum 5 users)
• Support all business applications with enterprise-class performance, security, availability and scalability
• Run on Windows, Linux, and Unix operating systems and easily manage with automated, self-managing capabilities

Streamline application development with Oracle Application Express, Oracle SQL Developer, and Oracle Data Access Components for Windows