Or composite rebar. Basalt fiber is sometimes used. Way cheaper than stainless and just as rust proof

‘a little more costly?’ Lulz.

316 is an order of magnitude more expensive than the crap used in rebar.

In project budgeting the material cost difference may well be relatively insignificant

Fiberglass rebar is comparable in cost, stronger, and not subject to water/salt damage. Rusting steel expands and cracks concrete from the inside, id want to avoid that. I’m actually building a pool right now using it instead of steel.