I would like to know what the best way is failproof your
SQL Server without using a
failover cluster requires an enterprise server which is not an option
Yes, Windows Failover Clustering does require Windows Enterprise edition or higher, but for SQL Server you need only SQL Server Standard Edition or higher. High availability (HA) solutions do have costs - and clustering needs shared storage - so my question is: perhaps the cost of being down is less than the cost of implementing and maintaining a HA solution? If so, that's absolutely fine.
Have you thought about log shipping? It's a more affordable solution but obviously is manual to invoke, and takes longer to come back up. Or database mirroring (marked for deprecation in a future version) offers HA and potentially DR too.
SQL Server 2012 also introduces a new HA solution, so you might want to have a look at that too.
If failover clustering is not an option, then database mirroring is your next best bet:
Depending on the client software used to connect to your database server, client sessions may be able to automatically failover between mirrored databases: