Business ethics Question
When Selling online, if two parties agree on price and exchange paypal and address info, is this a done deal? example, someone offers a pin for $10 and you reply that you would like to buy it. seller then says yes it is. what is your address and I will send you my paypal. Seller then comes back and says I undervalued this pin, I now want $35 for it. I have not yet made payment, just waiting to go to the bank to deposit money before I did. Is this acceptable behavior for selling?