OK, so this little TV-mounting trick is only no-cost if you've got a pile of scrap wood and a few heavy-duty bolts lying around. But even if you don't have a hardware store in your garage, this TV mount trick (adapted from an age-old builder's technique) will still cost way less than spending a couple hundred bucks on a new wall-mounted TV bracket.
Builders have been using the French Cleat for a long while. It's an easy, strong and versatile mounting system that, while most commonly used to hang cabinets, can be used to mount nearly anything.

That "nearly anything" includes flat-screen TVs, if you ask one helpful commenter at the This Old House online advice forums:
"There is an age-old, inexpensive, method for mounting cabinets and other heavy items that also works well for wall mounting flat screens. It is called a "French Cleat." The top block is screwed to the hanging object. The other half is attached to the wall. When you place the top half of the cleat over the bottom half, the item is locked firmly in position."

That's a diagram of a French Cleat at left. Assuming that both beveled blocks of wood are securely mounted to both the wall and the television, this thing can handle the weight just as well as a traditional wall mount for a tiny fraction of the cost.
If you need to tilt or swivel your TV, you'll need to buy a manufactured mount. But if you're just looking for a cheap way to hang your flat screen in the living room, this idea works—and it even keeps the TV closer to the wall for better cable hiding!
To get started with this project, check out directions and pictures of his French Cleat TV-mount setup from the commenter at This Old House.
(Images: Ikea Besta Hacked Into Floating Media Center, BHoweAndFamily.com)

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Totally not worth the cost savings. If this falls and it is an expensive TV, there is no way your renter's insurance will cover it. Don't buy a TV you can't afford the VESA mount for.
The only problem I see with this setup is tilting. I guess you could build the upper and lower cleats with different materials to get a certain angle, but it wouldn't be adjustable. Otherwise, very inventive!
If you're not up for this and looking for a tv mount that won't break the bank, check out monoprice.com I recently got a tilt mount for my LCD for under $20. It took about 30 minutes and the thing was up and running. Nice and sturdy too!
You'll most likely need new wiring and monoprice has great cables for cheap as well.
Ok monoprice, where's my free stuff for endorsing your site! lol
3 things. If you do this make sure that your tv is hanging far enough from the wall for ventilation. From these 'plans' you are going to overheat your tv very fast.
Also notice that this idea did not come from TOH but just someone posting in their forum.
Can you tell me where you get your bolts and cut wood for 'no-cost'?
I second the monoprice.com recommendation. they have very sturdy mounts for less than $50. the one i got was 15 bucks and my tv isn't going anywhere.
You can get really good tv mounts on amazon for much less than a couple hundred bucks!
I got one for my 32 inch for ~$30 (fully rotating arm) and for my 46 inch for ~$50 (tilt/low profile). Free shipping on both.
I'm with mauishopgirl got mine from amazon and it works great. For my particular TV I could mount any closer to wall and still be able to fit all my cables where I need them. One more thing to keep in mind. Otherwise, I've used this method for hanging cabinets and even a fairly large piece of art and can attest to it's success.
I will second the vote for monoprice. For $30 (incl. shipping) I got a low profile mount, HDMI cables and 2 boxes for running cables behind the wall. The mount is rock solid and has a 10 degree tilt as well.
+3 on monoprice - rig wood to the back of your tv or spend $25 on an articulating/tiling slim wall mount.
Hey...I can make a free toilet out of an old paint can!
I think some people are overreacting about the French cleat. It actually would make a good TV mount for little or no cost and the TV would be going nowhere.
That said, I just got an ultra-thin wall mount for my 55" LED LCD from monoprice.com and love it. Only cost $22 shipped and has a nice little retention rod so there is no way it can fall unless the whole wall comes with it.
well, for the record, i think the french cleat is a brilliant little technique. if not for a tv, then for plenty of other wall mounting challenges.
Note that a French Cleat depends on gravity to do the work. This will be a problem in earthquake country. Easily fixed by a wedge, bolt or the like to make sure that the cleat stays cleated even when the wall moves up and down.
I did this with a small 25" TV in my bedroom. I used a french cleat that I found in the picture hanging aisle of target. Used a piece of angled blocking behind it to solve the angle issue. It cost a whopping $7 for the cleat and a few additional bucks for home depot to cut the scrap wood. Works perfectly especially for such a small, and light flat screen.
When cabinets are installed with a french cleat, it is necessary to put a screw through the inside of the cabinet and into the wall. This prevents the cabinet from lifting up and out of the cleat.
There is no way to do that with this setup, and you could lift the tv up and out of the cleat easily by accident. Not a good solution if you have kids.
While we're all bashing this idea.... it's also not effective in low or zero gravity environments such as space, underwater, or homes in freefall.
LOL at Zekep's comment.
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