It depends on many factors, for example, the follower base you have or the niche your game corresponds to.
My experience and what I see in Itch is that a free game has many, many more visits and downloads than a paid game.
If your game is free, very few people are going to leave you a tip or donation, this is something you should keep in mind.
The most common model, and one that seems to be most successful, is to offer the full game for free and add an extra for a price.
For example, there are many VNs that are free, but they only offer 1 or two free updates for year, however, if you help the development, you have access to updates every month, etc.