When printing, there are numerous ways to save money:
* Print less. Reduce number of test/work prints and try to get to the final print quicker.
* Use smaller test strips (may work counter to no. 1).
* Be more selective in what you print.
* Print at a smaller size.
* Use a cheaper paper (e.g. RC instead of fiber, Foma instead of Ilford).
A simple fact of life is that chemistry consumption isn't a major cost driver in the darkroom unless you have an exceptionally expensive taste in chemistry, or you're being exceptionally wasteful. The former is alleviated by sticking to the lower- and mid-tier brands, price-wise (quality-wise, they're usually still excellent). The latter can be managed by e.g. using flat-bottomed trays and using a replenished developer and two-bath fixing so you don't have to mix everything fresh every time you do a session and you only have to replenish/replace what actually needs to be replenished/replaced.
If you're looking to further cut chemistry cost, the most obvious way is to start mixing your own chemistry from dry powders. This also comes with the advantage that you can experiment to your heart's content with different formula using a fairly basic set of 6-8 chemicals, which can be bought at a low cost.
One note about the 'eco' in product names - it's often unclear what this refers to. Are they referring to 'economic', or 'eco-friendly'? Who's to say? The real question is ultimately about things like the composition of the chemistry and its capacity (which affects efficiency, of course). In developers, the 'eco' label often refers to a developer that's based on a PC-backbone: phenidone + vitamin C/ascorbate as the main (sole) developing agents. Ascorbate is considered eco-friendly by many because it's a naturally occurring substance (although
this is technically true for hydroquinone as well). In any case, the environmental load of discarded ascorbate is effectively a non-issue, which likely is the main cause for the 'eco' labeling. The story behind phenidone (or its several variants) is that it's very efficient; only a tiny bit is needed to get the job done, which reduces both cost and environmental load. The drawback of these PC developers is that they're fairly unstable and often offer reduced shelf and esp. tray life compared to some of the more classic developers. The net result can be that the actual environmental load and/or economic cost
might end up higher for an 'eco' developer if compared to an alternative that can be used more efficienty, but is not necessarily 'eco' in its composition (e.g. a replenished ID62, which I use, and which involves extremely little waste).
For fixer & stop bath, the 'eco' thing is even more murky; it's debatable at what point an 'eco' adjective can be considered meaningful when applied to these products. Eco chemistry (both developers and fixers) might avoid the use of borates - but there are plenty of non-'eco' products that do the same. Stop bath in its essence is rarely an eco concern (either in an economic or environmental sense), and with fixer, the main concern is the silver that dissolves in the used fixer - and that happens regardless if those three letters are on the bottle of the product...
All this is not intended to brush aside the positive comments on users of these products - they work, and if people like them, so much the better. I only intend to provide a bit of background (and criticism) to that 'eco' label. There's a story behind it, and depending on what you're looking for, you may have to dig into that story to make the best choice. But in that sense, I stick with my initial comments, and focus on where the real costs are - i.e. the paper (or the film).
