I just use tall stakes pushed into the ground and garden twine.
Even simpler than the EMT trellis. Kind of a
Florida Weave. You just need tall sturdy poles and garden twine.
Start at one stake, around first plant and between the two tomato plants and tie to other stake, then continue around the back side of the near plant and figure 8 the two plants. Add figure 8s as the tomato plant grows taller as needed.