One of our end user reported below issue in MS CRM 2013 online organization, while trying to create order he was getting this issue.

Mostly this error comes when the currency used in sales entities is different than the currency used in price list referred in sales entities. But in our case, when we compared currency in order and price list used, it was same. But when we tried to set the same currency as default currency for this user, this issue got resolved!!

Hope it will help someone.