VS 2010 need to create a running total

I am still in the learning process with VB 2012. I have to calculate a total for a purchase. Everytime the user enters a price and clicks the add to sale button, it adds that price to the running total until they hit the total button. In order to have this running total, do I have to use a for loop? Or can I do the following:

total = Quanity * Price
temptotal = temp + total

totaldue = temptotal

will this setup keep a running total in the temptotal variable for me? Is my logic correct?

**I am creating this in a separate class**

Thank you for the help in advance!!