Plain old concrete rebar is available at hardware stores everywhere in 10'
lengths for about $3. It last years and years and years.

I would say it will last for your lifetime, and your kid's, and their
kids'.

It is rough, so that whatever you use to tie the tomoatoes (I
recommend pantyhose strips) wil not slip down.

I actually bought the 20' lengths direct from a concrete supply house and cut them into thirds, as the
5' was too short.

Yes. My tomatoes grow to six feet, so even a third of a 20' piece is
barely long enough, once you stick a foot of it into the ground.

vince norris