Hi Nikki,
A lot has changed over the years at Disney - including the way you purchase tickets. Unfortunately, you are no longer able to get a stamp to let you in the next day - no matter what time you enter a park.
Disney's current ticket program is called Magic Your Way Tickets which allows you to customize the way you purchase tickets. You have many options from which to chose.
MYW Base tickets allow you to enter one theme park per day for each day of your ticket. You can leave the park and return to the same park later in the day if you'd like. And the more days you purchase, the cheaper the per day price becomes.
You can add the park hopper option to your ticket(s) for an additional charge. This option allows you to come and go to MK, Epcot, DHS and DAK theme parks on the same day during the duration of your visit.
You could also elect to add the no expiration option to your base tickets (also at an additional charge) so that the tickets you purchase never expire. This is definitely the way to go if you think you'll ever be coming back (and who wouldn't???). Ticket prices typically go up every year so while it may seem like more money to pay up front, it will save you money over time.
If you still have tickets tucked away someplace that were purchased prior to 2005, WDW will still honor them - prior to 2005, tickets never expired.
For more information on other ticket options, click
here. If you run into further questions about purchasing tickets, please feel free to ask.