Can you tell us something about your network ecosystem? Do you have a server? If so what operating system does it have? Do you have applications like email (Exchange?) or active databases running? Are you looking just to back up the server or also clients? What operating systems to the clients/desktops have?
Tiny law office - 2 users. Have about 8 years worth of scans and word docs. I also want to back up my iTunes etc.
I have a tiny office catering to construction clients and do well, but we had a SHTF moment this week and my assistant convinced me we need to do this.