Using SQL Express edition commercially

Can I use SQL Server Express edition for commercial use?

Can our clients redistribute SQL Server Express edition with their application?

To redistribute SQL Server Express, you need to obtain redistribution rights from Microsoft. And yes, you can use it for commercial use (see, for example, this FAQ).

What are the Visual Studio Express Editions?

SQL Server 2008 Express and SQL Server Compact Edition – A powerful and easy-to-use set of databases to complement each Express Edition

Can I use Express Editions for commercial use?

Yes, there are no licensing restrictions for applications built using Visual Studio Express Editions.