I use concrete rebar cut into 5 foot lengths and driven into the
ground. Tie the tomato plants to the rebar as they grow. I have used
old panty hose because they don't chafe the plant like rope or twine
can sometimes. Now that the wife is retired, my panty hose supply is
diminished, so I have resorted to twine.

Another method that works well is to make a cage about 3 1/2 feet in
diameter out of some type of fencing about 3 feet high. I plant 4
tomatoes around the cage and begin filling the center of the cage with
composting material (grass clippings, kitchen waste, coffee grounds,
etc.) I drive the rods around the ring near the plants and begin tying
as described above. The plants are fed and mulched and grow well. They
seem to outproduce the ones growing singularly elsewhere in the garden.