With a tight budget, it makes it hard to get an enterprise commercial backup solution at lower than those unless you look at the open source area which tends to be less expensive (with support) or free (no support only community forum based support).
You may need to review what is the backup requirements and the desired backup targets?
Sample backup targets are like
Email (Exchange, Lotus, etc)
Database Servers (SQL, Oracle, etc)
File shares (Windows, Samba, NFS, etc)
Authentication (Active Directory, Novell, etc.)
Depending on how much data is required to be backed up, you can look at the option to do online offsite based backup (internet-based). That can be cost effective with a dedicated support team. I've seen some small shops go with something like E-Vault. But the limitation would be your bandwitdth. If this is an option, you can look at Barracuda Network's backup service which would provide a local (onsite) backup solution and then offer to "replicate" to offsite locations (Barracuda Network's managed). Link for that: http://www.barracudanetworks.com/ns/products/backup_features.php
Hope this will direct you to some options outside of the those you requested.
Depends on what you want to backup. Some online backup or network backup software are pretty good and can meet most of the needs. We have had NetCDP (www.netcdp.com) for our Windows servers to back up to NAS servers and also back up to S3. We also had some servers using Jungle Disk. You can try them out to find out if they meet your needs.