Monitors aren't that expensive any more and they are getting cheaper all the time. The stands to hold them? Now that's where I ran into problems, it was going to cost more for the stands then the monitors! So I wound up making my own. I also put the computer together. I'm 58 and need larger print any more, those days of reading small print are long gone for me so I wanted some monitors that could better display the information I need.
Here is one of the best sites I've found to get some ideas of multimonitor setups. Click the Gallory for ideas. I've thought about getting a couple of wider monitors for one of the stands to display more information. I really ought to have a better back up system. Always something......
Here is an excellent site for multi monitors.
Multiple Monitors.Org - Home of Modular Multiple Monitors, Multi-Displays, Multi-Monitors for Desktop - Video Wall Applications