Hi there, Sherry!
Welcome to planDisney. It looks like you are putting the finishing pixie dust on your visit for next week. If there's one thing I love, it is a souvenir popcorn bucket or character sipper to take a little piece of the magic home with me. We've got quite the collection going on over here, and we love to reuse them or put them on display to remind us of some of our happiest memories. 
Generally speaking, if a collectible, such as a popcorn bucket or sipper, has a promotion running alongside it, such as free refills, it would only be good for the season within which the collectible was offered. In other words, it would not carry over to another visit. Currently, I am not aware of any promotions on sippers that include free refills. Typically, the purchase of a sipper comes with your choice of one fountain beverage, and of course, the joy of the sipper itself that lasts forever! I'm sorry if that was not the news you were hoping to hear!
While you are visiting between 
Halloween Time (ending October 31st) and the 
Holidays (beginning November 14th), there may be limited collectibles available during your trip. However, if there are any in stock, you can actually mobile order some of these items directly from your phone, which I have done for a few coveted sippers like the current Pluto Skeleton Sipper. I love the convenience of knowing I've secured this adorable souvenir with just a few taps in the app itself. Head into the app and tap the "+" in the bottom navigation bar and select "Order Food". When you go to place a 
Mobile Order from a quick-service restaurant, you can filter at the top to show just the "Seasonal Offerings". Immediately, you will see what limited-edition items are currently available, from treats to sippers. With a quick add-to-cart, they can be yours, pending availability. When your arrival window opens up, head to the location and tap "I'm Here" in the app. In just a few moments, your order will be ready for you. 
One of the perks of visiting next week is the ability to experience 
Haunted Mansion Holiday, Jack Skellington's 
Nightmare Before Christmas takeover of this fan-favorite attraction. I love that this is available from Halloween right through the Holiday season for Guests to experience. It's my favorite overlay of the year, and you won't want to miss the gingerbread house in the ballroom. It's handcrafted every year to be a one-of-a-kind sight to behold. 
Sherry, I know this may not have been the news you were hoping to hear, but I do hope it's been helpful. If you have any more questions as you gear up for your visit next week, come back to see us here at 
planDisney.
Magic awaits!
Tara