When my daughter was in daycare and kindergarten last year (at the same place), I put together one basket for the two K teachers and another for the six daycare ones. On the advice of a friend who works at a daycare, I filled it with snack food and I also included coffees, teas, and hot chocolate. If I had to guess, I would say I probably spent about $25 plus for the K basket and $35 plus for the daycare one.
When my daughter was at an at-home daycare, I got her caregiver a $25 gift card to a restaurant. Much easier (i.e., cost-effective) to do when you have only one person to buy for.
This year, because I am underemployed, I bought my kid's first grade a teacher a coffee mug with bath stuff. I thought it was cute and the price was right (around 5 bucks), but I am sure she would much more appreciate a gift card. I figure she can regift it if she does not like it.
I have heard teachers appreciate gift cards to stores like Holcomb's, but that went out of business, so not sure what the alternative is. Probably can't go wrong with Target.