Many folks like to build their own tomato cages. There are a few advantages to making your own cages. If you buy materials like a roll of chicken wire or reinforcing wire, the cost for several cages is much lower than buying individual cages, unless you buy them in bulk.

The most common way to build tomato cages is to use either a chicken wire fence or concrete reinforcing wire. You can find either of these with a mesh that's large enough to put your hand through, which will allow easy harvesting of the tomatoes when the time comes. The fencing is looped back on itself in a way that forms a large tube, which is set over the tomato plant and it grows up inside the cage. With this approach there is not as much need to tie up and prune the plant, the plants will just climb through the holes and naturally support themselves.

Another way to build cages is to use PVC pipes. These can be very durable and sturdy, as you can glue up a permanent structure. Alternatively, if you just snug the parts together it will often be sturdy enough, but will easily disassemble for storage, which is one of the biggest problems with tomato cages. And many people will make cages from wood, although those tend to not last as long.

There are other similar techniques like the Japanese tomato ring (which is actually an American invention) that combine a large home made ring with some intensive gardening techniques to boost the yields of your tomato garden. This is not something you will find you can do with a commercially produced tomato cage.

Another common way to support tomatoes is to build a trellis with a pipe that runs along the row of tomatoes and then strings are tied to it and the other end of the string is anchored in the ground near the tomato plant. Then the tomatoes are tied to the string and they can grow as high as they like and just climb the string.

But one advantage to buying tomato cages or supports is the wide difference in how the problem of supporting a tomato plant is approached. You can find some that are simple cages, with 3 or 4 rings in an expanding radius as you move to the top. There are some spirals that are simply stuck in the ground, and the tomato plant is tied to it as they grow. SImple plastic or bamboo stakes are often used.

There are square tomato cages, that are actually four sections of mesh that form a small square, but have the advantage of unhooking and folding flat for storage. The are 3 sided versions of this same basic idea as well.

Of course, if you are using a hanging tomato planter, then the whole problem of which cage to use is not an issue, as there is no need for tomato cages for plants that are hanging from a container. There are other advantages to hanging planters as well...