V4V is just tipping. Tipping is not a valid business model. People will never voluntarily tip you the value you expect because people have a hard time assessing absolute values of things on their own on the spot, they are better at seeing a price and then making a binary yes/no decision about whether the value justifies the price--YOU have to set the price. It is hopeful to think that you can sustain yourself with the generosity of plebs, and in some communities charity and generosity does sustain people (e.g. the church), but I think in this case it is unrealistic to rely on the generosity of random people on the internet