The amount you bill has to be directly proportional to the amount of skin you have in the game.
For example, look at auto mechanics. You have the professional guy with a nice shop, waiting area, loaner car, alignment rack, tire machines, scan tools, etc. If it's broken, he can fix it. He likely charges from $65 to $125 per hour, depending mostly on where you live. Cheaper out here in BFE. Much more expensive somewhere like Manhattan.
On the flip side, you have the "mobile mechanic" guy who has a rusty Chevy Astro van and some Pittsburgh tools. He can do oil changes, brake jobs, maybe wheel bearings and basic electrical stuff. He may not have insurance. He may want to be paid in cash. He will likely vanish like a fart in the wind if you have any issues with the work he has done. This guy charges anywhere from $15 to $40 per hour, depending on how rusty the Astro is and a few other factors filed under the heading "shady".
Now, the world needs both. They exist mostly in parallel, with each serving a different clientele. But, they both claim to be mechanics.
Same for programming. Are you doing fixture design, cycle time guarantees, tool specs, tool life estimates, 3D tool paths, 4 or 5 axis programming, exotic materials, micro machining, etc? Do you have liability insurance? Do you offer any guarantee of your work?
Or, are you writing 2.5D programs from your easy chair with a free seat of Fusion and a can of Pringles?
Personally, I think it's a long shot business model unless you have a slug of known clients who need your skills and know what you can do. I've been programming a while now, and I still almost always have to post a program more than once due to simple errors or miss matches in my tooling. I can't imagine trying to sort that out over the internet from some remote location.