This is a thing that should generally be planned from the start of the design. If you have designed and produced something meant to be sold, you are making sure to take all consideration of things like audience and competition into account. And for the prospective consumers who are not comfortable with buying from an unknown publisher, you're publishing a free separate demo version so everybody can try before they buy.
If your product wasn't planned to be sold, then those considerations have been weightless, and you've probably made a game best put up for free.
Like androidlove I also have no income, so the only things in my life are whatever is made available for free, and the people publishing free games might be the only reason I haven't gone insane years ago (at least I think I haven't...) . Buuuuut itch takes commissions from sales and I <3 itch so I appreciate also those creators who are selling their games because they are supporting the itch that makes all these free games in one place possible. So, create something silly and simple to share with us all for free, or create something marvelous enough for people to pay money for. Whichever is your inspiration, you are doing it in the right place.