Nice chat and responses. Beautiful to see Goodwill is not dead in this day and age. Extending acts of gratitude can very often deepen their convictions about what they do in their lives on the daily basis.
Because their job is one if the most important and IMO they do not get paid adequately for themselves or supplies. My dds Kindergarden teacher gets $100 a school year to buy supplies for a class of 27. That price includes paper :/
How about because they are under paid and put up with a lot of bull from other people's kids and showing them some appreciation will probably make them feel good. It doesn't have to be expensive, a $5 gift card to starbucks or sommething is nice.