I've seen a lot of creative ways to wall-mount monitors on the cheap, so I thought I'd share my setup, which uses three different techniques which I haven't seen around. This incorporates one 21" widescreen and two 17" 4:3 displays, which are driven by a Radeon HD3850 and an HD3650 (which is stuck in a modified x1 slot, but that's another instructable). The left monitor is angled and the center and right one are flat, because the array is off-center to me at the desk.

This is not a step-by-step tutorial, as this setup evolved over a year or two, and I just decided to make an Instructable to share.

UPDATE:

I've gotten another Dell monitor identical to the one on the left and replaced the silver-framed one. Now the whole setup looks much more professional, as well as better display, with the better quality monitor and matching brightness-and-color.

Step 1: A Solid Foundation

First, I mounted a nice sturdy piece of wood to the wall studs so that there would be a good place to mount the monitors. The strips on the top and bottom were added for the center monitor, which was done later, as described in a later step. The two silver screws that are not driven all the way in are for hanging the right-hand monitor, which is how all three were originally mounted.

Step 2: With Some Help From the "helpful Hardware [wo]man"

Each monitor was equipped with two little keyhole brackets screwed into the VESA mounting holes. These simply hang on the screws that you saw on the previous step. I got the brackets and screws from the local hardware store. I LOVE that place. Just walk in, tell the lady what I want, and she leads me around the store to all the right things.

Step 3: No VESA, No Problem

My 19-inch center display went bad and I good a good deal on this 21-inch acer, but it has NO VESA MOUNTING HOLES! So, I had to come up with another way to mount it. What I came up with cost me nothing, as I already had some of these curtain rod brackets in the shed. There are two on the bottom, with the hooks facing upwards, and two on top with the hooks upside-down. It all goes together pretty easily if that brass screw you see on top is the LAST part you assemble, with the bottom edge of the monitor resting in the bottom hooks. A little electrical tape hides the ugly brass brackets, though paint (or even PlastiDip) would have probably been even better. Here you see the original mounting panel was not wide enough for this, so I added a strip at the top and bottom to accommodate the brackets.

Step 4: A Little Extra Bonus

I wanted to hide the brackets and the big gap behind the monitor, at least from the top, so I cut a scrap of old laminate flooring to rest on the top brackets, forming a little shelf. Perfect place for a webcam, volume control for the sound system, and a USB extension (with Bluetooth dongle).

Step 5: Looking Good From Any Angle

The way the room got (re)arranged, my desk is now off-center to the monitors and, consequently, looking at the left one was like looking "way over there." I tried to dream up some cheap way to mount it on an articulating arm or somehow angling it so that I could use it effectively. Finally, I came across this old steel bracket that, 15 years or so ago, held the "car phone" in my company van, and was one of those things I put away thinking that it would be useful some day. All I had to do was rivet it to a plate cut from an old monitor stand (more stuff saved "just in case") and screw it up to the wall

Now all that's left is to paint the wood to match the wall, tidy up the wires, and dust (AGAIN!).