Trying to distort the market so that lower priced items are more profitable is quite challenging to do without unintended consequences. A progressive consumption tax would definitely be a worthy experiment

When I say it should be free, it means that there is no cost to be paid by individual

No, I don’t support UBI, but I support UBS - Universal basic services. Food, housing, water, education, etc should be free at a basic level. Basic level for housing for example will be ‘Housing First’ concept in Finland.

It’s relative mass that matters. Weight of a car to the weight of a person is so high that a vehicle being 5 times heavier than another vehicle is irrelevant.