Many of us plant that many tomatoes or more annually and every approach except sprawl is going to cost you up front. So it just depends on how much you want to invest and how much routine daily work you can do on them.

Wood stakes if you plant to prune them heavily. But they have a short life span and tend to rot at the soil level. You can use metal T posts - many do - but 150 x $2 to 2.50 each. Work is driving the posts and pruning and tying up the plants.

Next least expensive IMO is Florida weave. Cost of the T posts but less of them and lots of string. Plus lots of work pruning and keeping them tied up.

CRW cages is what I use on most of mine but I have accumulated them over many years so the costs and work to make them has been spread out. Plus I have the room to store them during the winters with no problem. And you still have the additional costs of stakes for them. Advantage - minimal to no pruning and more production.

Cattle panel trellising is my other support system. At approx. $25 each plus the cost of the T post stakes to support them at approx. $2.50 each. You'd need 8-10 panels plus a minimum of 3 stakes each. Winter storage issues too if space is limited. Work is driving the stakes and hanging the panels but then a weekly weaving and/ or tying up of branches is about all you need.

Hope this helps.

Dave

Staking can be even more economical/practical if you plants several of the matoes in a row and do a combination of staking and weaving. I have found out that staking is more practical if you also do some pruning, keeping the number of branches down to about 3. I personally do staking mostly.

I make my own stakes from cedar boards. Some use EMT. That is equally good. But use minimum of 3/4" diameter for sturdiness. 1/2" REBAR is yet another option.

Leach? No. Flake off over the years as rust develops? Sure. Is that a problem? No, why would it be?

Dave

Not as sturdy so takes more care in storage but more flexible and easier to work with, comes in several gauges, sold in bigger rolls and for less money per cage, and doesn't rust.

You'll still need stakes to hold them and depending on the weave hole size bought you may have to cut some larger access holes in them. But it is a workable option.

Dave

I'm wondering whether any of the chemicals in the paint may be absorbed by the veg. plants, over time.

Nothing else as economical as that except perhaps PVC. 100' of 1/2" PVC will cost you about $15. Figure on a support every three feet with the plants planted one foot apart. I would build a giant rectangle so the entire thing would be self-supporting. Build it 2-2.5' tall and just drape the plants over it. If you build it 2' tall, your tomato plants would each get to 4' in length fully supported. That's at least as good as a typical cheap wire tomato cage. Just clip them off as they reach the ground and encourage them to bush out. You'd need a little more than 200' of PVC plus 50 1/2" T fittings that cost .35 each. You could just dry fit the whole thing so you don't have to spend anything on PVC cement. That's about $50.

A Florida weave, as mentioned is a great option. But you'll need a minimum of 15 T posts that run at least $4 each. That's leaving a 10' span which is probably too much for how huge tomatoes get. I'd use double that personally. Then you're going to want to use a really good twine or if you want it to last for a few years, nylon string.

Plant systems don't work that way. They have a very active filtering system and if they didn't, given all the things that are naturally found in dirt, we'd all be eating contaminated vegetables. :)

This is not to say that one should freely add anything they wish in the way of chemicals to a garden, they shouldn't. But some paint flakes from a T-post scattered over the soil over many years, even petroleum-based paint if that is what is used, are a very infinitesimal part of garden soil overall. Plus many of the components of paint are volatile chemicals that evaporate into the air.

So think of it this way, we walk in our gardens and track in all sorts of things, we use metal tools, metal cages, plastics of all kinds, cars with exhaust drive by, dust and fungus and bacteria drift in from all over, etc. The garden isn't a sterile or even a clean place so if the plants were going to suck up all the contaminants then we'd all best give up gardening.

But if it concerns you then you can always re-coat the stakes with fresh paint or scrape it off before using them and just let them rust. Rust (iron oxide) is a normal component of soil anyway.

Dave