I have been using multiple monitors for about 10 years both at home and work. I think that having only one or two puts you at an extreme disadvantage in so many ways. Having three or four or more is essential to get high-speed work done.
Having multiple monitors using video cards is the best way to go but will require a large computer and typically a workstation. But if you don’t have extra slots and more than one video card, there are a few good USB devices available. The J5 Create USB to VGA and the Kensington USB 3.0 Multi-Display Adapter both work great and the prices are below $50 each. They have an adapter for both DVI and VGA so you can actually use any old used flat-panel such as a Dell flat panel. A 17 inch is fine because the 17 inch monitor has the same resolution as a 19 inch monitor and requires less space, especially when mounted on a multi-monitor arm. You can get these monitors on eBay or Amazon for around $45. Kensington says that you can run up to five extra monitors from even a laptop. I have found that running a few extra monitors via USB works great, I can’t even tell the difference from the monitors that are running on a video card. They display great without any weird glitches, they are fast and you can run movies. The J5Create product is equally as good. I have a few of them running along with a couple on my video card and when I’m doing websites or Internet marketing or creating business listings for companies I find that I am at least 40% faster than if I only had one monitor. My whole goal with my company is to create a lot of quality content really quickly at one half to one third of the price of a big marketing company or big marketing agency.
So for less than $300 I was able to add three monitors to my system. I also like using the multiple arm stands, I like the Mount-It! MI-756 Multiple 6 Screen Articulating product.
Something I really love about Microsoft Windows is that it supports multiple monitors very very well.