What is one price, no bargaining, one price?

the information about price is asymmetric between buyers and sellers.

the seller is willing to raise the price

the buyer has the requirement to lower the price.

the seller has more information about the price, which is known by the buyer.

so when the seller gives the price, the buyer always thinks that the price given by the seller has moisture.

So the seller gave the statement you listed, which means to send information to the buyer. The price can't be lower.