Cages

We had seen this article in This Old House magazine where they used posts and twine to hold up their tomato plants. Being the thrifty gardeners that we are, we tried it. As soon as the plants hit about 4 feet tall, they started to droop terribly. The twine was not strong enough to hold up the gigantic Roma plants. So we gave in and bought cages. Now the plants are growing straight up the cage and not drooping. Oh well, we tried. How do you hold up your tomato plants? Do you have a DIY solution?