SQL Server Express would probably be your best bet for the time being. It's free, it supports databases up to 4GB, it has tight integration with VS and it uses the same database format as SQL Server so an upgrade later is seamless.

__________________

2007, 2008, 2009, 2010

Why is my data not saved to my database? | Communicating between multiple forms
MSDN: Data Walkthroughs | "How Do I?" Videos
My Blog: Custom Events | Dynamic GDI+ Drawing