Parece muito interessante ter um banco robusto como oracle para pequenas apps e free.
Oracle Database 10g Express Edition: "Oracle Database 10g Express Edition (Oracle Database XE) is an entry-level, small-footprint database based on the Oracle Database 10g Release 2 code base that's free to develop, deploy, and distribute; fast to download; and simple to administer. Oracle Database XE is a great starter database for:
* Developers working on PHP, Java, .NET, and Open Source applications
* DBAs who need a free, starter database for training and deployment
* Independent Software Vendors (ISVs) and hardware vendors who want a starter database to distribute free of charge
* Educational institutions and students who need a free database for their curriculum