Instead of purchasing a license for the SQL Agent, here is what we are doing to backup our MSDE database:
Create a Scheduled Task using the path to osql.exe like so:
F:\MSSQL7\Binn\osql.exe -Usa -P -i f:\mssql7\jobs\BESMgmt.cmd
And the BESMgmt.cmd contains the following: (replace the BESMgmt with the database name you want to back up)
backup database BESMgmt to DISK = 'F:\MSSQL7\Backup\BESMgmt.bak'
backup database master to DISK = 'F:\MSSQL7\Backup\master.bak'
backup database msdb to DISK = 'F:\MSSQL7\Backup\msdb.bak'
This backs up the databases BESMgmt, master, and msdb to files which are then backed up to tape at night.