This is my first attempt at a DIY home vacuum chamber for sous vide and marinating food in the kitchen. I spent about $170 including the cost of a new vacuum pump. Here's a demonstration:
The chamber is a flat piece of high quality plastic (polycarbonate) laid on top of a flat pan or bowl. Rubber matting is used to create a gasket between the pan and plastic. A normal automotive pump then sucks out the air. With this simple setup I can pull a vacuum to 29" of mercury according to the cheap gauge I have, which I understand is better than commercially available vacuum sealers.
One of my goals was to have a setup where I could re-use the bags. Instead of heat sealing plastic bags I put the food in Ziploc bags with the slide sealer. I then use magnets on each side of the polycarbonate to close the bag inside the chamber once I pull out the air.
Before you start out, there are two things you need to keep in mind:
If you use a good vacuum pump you are dealing with very high pressure. Atmospheric pressure is over 14 psi which doesn't sound like much until you realize that 1-foot cube has just over a ton of pressure on each side. I crushed a thick metal pan (see picture) that I thought could handle the pressure.
Keep your fingers away from the air-intake of your vacuum pump. It will tear or rip off your skin in no time. You are a complete moron if you check to see that your vacuum is working by using your fingers to feel for air. Do not ask me how I know this.