I would use website all traffic CVR as a benchmark to start. Say 1% fill out a contact form to talk to you, 50% turn into customers. Contact form value is 4k.
For paid it’s fairly straightforward if you’re good at keyword research. You can get average CPCs from Google Ads. Rough math says you can pay up to $40 CPC to break even (but that’s revenue, not profit! More likely it’s less than that significantly). If the CPCs are too high. You can’t run ads (unless you build out a retargeting marketing setup). Move on.
For paid you can run an experiment with your top keywords (again you’ll need to be good at keyword research to do this). Get 200-300 clicks. If you’re paying 2X more than you’d like for a demo, you can probably adjust it and make it work. Beyond that and you’re likely not in the right spot.
I can go on and on about this (it’s what I do for a living)
SEO: it can be powerful, but depending on where you start (domain authority, backlinks, current content) you might not be able to lift this off quickly,
Social: this one is probably the most powerful. Takes consistency! My boss built his 20mil company off social media. If you have a unique solution to a painful problem. Go here. Find your audience. Talk to them (but don’t hard sell)