How is it decided what your medicare payment will be each month?

I will be on medicare in a few months but have not signed up yet. All I can afford is the standard $170 that SS takes out. That’s what my neighbors pay also. How is that decided and if I sell the house and have more money in the bank will the medicare payment go up?
All I can afford is the standard part A and part B but if the house sells I could potentially add more services.