multiple variables in one label?

[personwhoishere]

Ok, so I have to make a project that calculates movie rentals. It has different prices for DVD's, VHS's, new releases, member discounts, etc., and displays the total of the entire order once it's finished. I've gotten most everything to work, but after I clear everything, I want the subtotal for the previous movie to be stored, and added to the subtotal of the next one, but have them displayed in the same label, but not at the same time. Maybe have the subtotal for the first one stored in a variable somehow? when everything is cleared, and then add it to the subtotal of the next movie, and then display the total price of the order, which would combine the prices of both movies. I hope that makes sense. Thanks in advance to anyone who is willing to help.

[debasisdas]

you can store the previous subtotal to avariable or fetch from DB and add to current month total and display in the label.

[personwhoishere]

How would I code that though? That's what I wanted to do but I couldn't figure out how it would work.