>...I absolutely think I ought to be taxed a little more than I am, and would gladly pay that money to live in the better society I believe that would create.

The federal government does have a system to accept gifts which you might want to check out: https://fiscal.treasury.gov/public/gifts-to-government.html

Whether your gift will make a better society, I can't know - much like your taxes you have very little control over what the money is going to be used for.

>...(there can be no such thing as a free market when such a small number of individuals control such a large proportion of the spending power).

A free market is generally considered a system where there are voluntary exchanges between buyers and sellers based on mutual benefit. It seems odd to claim that since there are some very wealthy people in the country that somehow a consumer can't buy bread from a baker, etc. Maybe you can expand a bit on how you are defining free market.