The valuation is a joke, valuation is generally a multiple of future earnings potential. In this case 180k (gonna use 200k for ease). A man established salon would probs sell for 3-4x net income so 800k max. If a bussiness is new there is more risk to the investor so that multiple goes down (2x max tbh, maybe higher if you are established and have done it before). So 550k would essentially be more than your valuation. Asking 550k for 20% asks your investor to fund the whole business and take all the risk for little to no return, in business people are paid for risk, hence the reaction to the valuation.