I substituted for years and always carried a bag full of stickers and awards (small candies, crayons, colored pencils, etc). I also bought some supplies for projects I came up with. I never spent much. They all came from the dollar store.
Mine did, too, as much as possible. I was always looking for sales and for plans for "emergency" classes for when there were no plans. I NEVER wanted to have to tell on a teacher because I was left with nothing for the students to do. (there were times when I had to)
In most situations, the students appreciated that what I was handing out was 'my" supplies, not the schools.
This experience is why I'm uncomfortable with the protests. The teachers are making it all about them. What about that lower tier of school employees who aren't as well off as they are?