lottery inventory control in excel

Hey folks I am trying to get this lottery inventory sheet i made in excel to work perfectly, I have all the basic functions set up right, what I want to do now is if you look at the excel sheet i posted it has closing for all days(1-30).

Here is how it goes:

amount / total tickets / opening / day1close / day 2 / day 3 ..........day 30
50 / 20 / 1 / 10 / 19 / 3



it gives me the right totals, but lets say i want to put a different ticket in the slot but its amount is $20, how can i go about doing this so it won't affect the ticket sales for previous days as the previous days had the different ticket which was worth $50 and now this new ticket is worth $20.



also pls look over and if you can give me tips on how i can improve this thx