Is there a price limit to what is considered a snack on the DDP?
*In general*, it's any single-serving snack-like food item under $4.
But each location decides what is considered a snack item beyond the items listed in the official brochure. The official items being: frozen ice cream novelty, single-serving box of popcorn, piece of fruit, bag of chips, bottle of soda or water, medium fountain drink, coffee, tea, hot chocolate, or single-serving milk or juice. Anything beyond that is up to the management of the food location.
You have to check the menus for the purple-and-white DDP logo to see which items are considered a Snack. You can't strictly go by the "$4 Rule".
For example, at Flame Tree Barbecue, Onion Rings at $3.79 is a Snack credit, but a Basket of Fries at $3.49 isn't. (Don't ask me to explain it, just going by what the menu board says)
-Rob