I have participated in this competition before. There was something I wanted to write there, I want to announce it here. Due to the volatility of the steem price, the seller must receive the money of the product sold in a very short time, otherwise it may cause great losses and cannot supply the product. The second point is that the price of the product should always be kept up to date on the web page. In other words, the web page where the seller will enter the price of the product in dollars will automatically convert that price to steem and keep it up-to-date. I wish you success in your work.