Metal tomato cages have three support rods with rings spaced at intervals around them. Pushed into the soil around the tomato plant when it is young, the vines are propped on top of the cage rings as the plant grows. Their support keeps the tomatoes off the dirt and the vines from cracking under the weight of the ripening fruit. They are easy to use, reusable and relatively cheap. Homemade cages can be made from cheap concrete reinforcing wire. A 5-foot length of 10-gauge wire with 6-inch openings with the ends wired together makes an 18-inch diameter cage 5 feet high, suitable for the tallest tomato plant. Remove sections of the horizontal wires from the bottom 8 inches and anchor the vertical wires into the ground. As the tomatoes grow, turn the vines back toward the cage for support.
Three, 5-foot 1" wooden stakes sunk around a tomato plant and tied at the top make an effective and inexpensive cage. Attach screws or nails to the boards at 1-foot intervals and run a heavy cord around them to make rings. These support the vines as they grow. YouGrowGirl.com recommends you recycle old pantyhose or nylon stockings by cutting into strips and using them. They make soft, non-damaging tomato ties. As the tomato plant grows higher, add more rings to support the top vines. These are a cheap, adaptable and reusable solution for supporting your tomatoes.
Tool handy gardeners can turn a flat trellis into a box cage for their tomato plants with inexpensive wooden lathes. These are reusable and fold for storage between seasons. Get four 8-foot,1 inch by 3 inch boards for the corners and two 21 inch boards, two 19 inch boards and two 17 inch boards for the rungs as well as two 20 inch boards for braces. Screw the 21-, 19- and 17-inch boards to the long boards a foot apart, starting 7 inches from the bottom of the 8 foot legs. This will make two angled ladders. Connect these ladders by screwing the two 20-inch braces on either side about 30 inches from the bottom of the long boards. Place these cages over the tomato plants and brace them by burying pointed stakes near the bottoms and nailing or screwing them to the trellis legs. Hang the vines over the rungs as they grow. When ready to store, remove one screw from each brace to allow the ladders to fold together.