I found some Disney candy canes @ Dollar General so this past Christmas trip, I left a couple of those along with my Mousekeeping envelopes. I took some of the candy canes with me to the parks each day, too, and left them for wait staff at the restaurants.
We made our own envelopes, too, with stickers from the dollar store, and I wrote different sayings on them, like "Thanks, Mousekeeping" or "You're the Best", and then "Good-Bye" on the one for the last day. I used red & black markers, and tried to make it look cartoony amd already had the money in them before we left, too.
I posted a while back for someone that was flying with small children to take all their envelope making supplies on the plane as an activity to pass the time.