(I'm just saying this so Dasius might see, but you could respond to it if you want)
Would it be possible to assign a value, zero, to each item and then when the code sees the first item, it checks to see if its value is one. If it is one, it skips the item check for that item. If it is zero, it does the check. If it is not a match, it sets that item's value to one. If it is a match, it sets the item's value to 2. Then it goes along with all the other checks and then loops. For every check, after checking if the value is one, if is not, it checks for 2. If it is 2, then the customer buys the item. This value system might eliminate the loop of checking one item over and over again, because if it is not the item the customer wants, it will skip the check... hopefully. I am not very good with coding, so I am guessing what will work.