It's an interesting project, clearly stemming from scratching one's personal itch. Congrats on the Show HN, always an exciting experience :)
A bit of a reality check though if you don't mind - I think you will have very hard time selling this.
Windows chunk of your target audience will undoubtedly be already using Far and its many plugins, and thus have very little reason for switching. Conversely, those not familiar with Far probably won't be that interested in fman either.
Mac - desktop Mac market is exactly 1/10 of that of Windows. Perhaps Mac people are more inclined to pay, but it will still be peanuts compared to what a Windows version could bring.
Linux - I am frankly not familiar with a single Linux user, developer or not, who ever bought anything except for games.