Are you talking about the Candy Bar sales?  That is going to last for most of the game.  Each release will add a few more locations.

The primary intention of that part of the game is to give Callie a chance to make a little extra money.  I don't want to give anything away, but if she doesn't have all the money to turn in when the time comes, all hell will break loose.  At the current time, it does not have a completion yet.

Other things will present themselves throughout the game...particularly after Callie joins the Dare Club.

There's a post in another topic that pretty much gives a list of all the current people who will buy candy bars..most of them during the Afternoon.