When should I get a professional Amazon seller account?

You should look into getting a professional Amazon seller account when you want to sell more than 40 products per month. For a standard Amazon account, you pay $.99 cents per sale. So if you are selling under 40 products a month, you save some money going with the individual account. But if you begin to sell more than 40 products per month, that's when a pro-seller account would start saving you money.