Hi Beverly, if it's for tomatoes, then I recommend using a pole and gently tying the main trunk of your tomato to the pole as it grows.
It would probably be cheaper and easier to just buy them unless you have something really exotic and complicated mind.
What you could do is put some posts in and run a grid of wire or plastic line.
here are how to videos you pick https://www.youtube.com/results?search_query=diy+tomato+cages
you can buy a roll of 3 ft high fencing cheaper than the cages and make your own. these work well. anchor to ground with bent pieces of heavy wire (like coat hanger sections) bent to a "U" shape. the roll should make several cages.