I'll keep it free for as long as possible, because I remember when I was a kid in school who only played free games on the internet.
However, itch.io has a limit of 1 GB for game projects. If the files for VT exceed that I'll have to take it to Steam, but that won't happen anytime soon because I think it's only 200 MB (0.2 GB).
When I take it to Steam, I'm not sure what I'll do. If the game is finished then I'd want to sell it for a few bucks (because I'll have spent years working on it) and have a downloadable demo on the store page, but if it's still in progress when I have to take it off itch, then I'll mark it as Early Access and make it free.
Anyway, all of this is a long way off. It probably won't happen for another year if it ever does. I'll post a dev update if I notice the game size getting close to the limit.