If you have MS Office you can install a desktop version of SQL server. It will probably be SQL 2000 but it works just fine moving your work to SQL 7 as long as you aren't talking about DTS or features specific to SQL 2000. If you're just talking about creating tables and working on queries it should work fine.
MSDE is functionally equivelent to SQL Server, but without the client tools and tuned for small loads. The code you write should/will be 100% compatible I understand :-)
you can use the Client Tools from a SQL2K Trial Version with MSDE, they work just fine and the client tools in the downloadable trial version don't expire either. If you look around should be able to find a download of just the client tools somewhere too, will save you downloading 300Mb when you only need about 50mb of it.