Gifts for Daycare

I’d like to give my son’s daycare teachers gifts for the holidays. I’m thinking Starbucks gift cards but I’m really stumped at how much I should get them for. What’s an appropriate/reasonable amount?

Also, his room has two main teachers who are always and only in his room. There are two regular fill-ins/helpers who also do the same for other room. I’d like to give them all gifts - should I do more for the main teachers and a smaller amount for the helpers?

Thanks for any/all input!