Once you have activated a rule you can set how much points you want to give to customers for completing the action. By default 100 points are worth $1 or 1 unit of currency depending on your currency. So if your currency is EUR, then 100 points are worth €1. If you decide to give your customers 200 points for signup to your online store it means they will get $2 credit. If you set it to 400 points, it means they will get $4 credit and so forth.