I have about 200k on my main character but it could be spent in minutes even on things I consider quite basic, because I’d probably want a lot of stock to do me for a while. I don’t know how much coin I’ve had and spent over all my play time but it certainly hasn’t been as high as some more dedicated players.
Honestly, I can’t say what other players do for their millions, because I don’t know exactly; what I do, is what me and @Nightstar already discussed at some length, ages ago on this thread:
See also for some context:
Mining for fossils (medium/large) and minting the results with a fully coiled Chrysominter is what I still do for most of my coin on my main character, as I have not owned or maintained a serious shop for a long time now; however, on the alt I have been playing from scratch with my partner has probably amassed/spent more than 100k by now even only in a short time of playing.
@bucfanpaka’s recommendation for 3x3 mining is very good too. And it’s not only gems and coal; the metals, especially silver and copper, always seem to be in good demand. It all adds up.
Edit: Before I forget. Wheat and oat farms tuned for high yield can make a fair bit of passive money every day if you have the patience for farming and to then wait for the wheat to become flour. I don’t know how much market demand there is for bags of flour, but at their base worth thrown in the minter, they’re already pretty good for a very low amount of effort, albeit boring effort.