I was a preschool teacher for many years, and I'm also a parent and grandparent. I feel that gifts for teachers should be each person's individual decision - what to give, how much to spend, and even whether, and when, to give a gift. It's true that teaching isn't a very high paying profession, and I think every teacher appreciates gifts, both personal and for classroom use.
However, parents all have different incomes, budgets, and financial responsibilities. I don't think parents should feel obligated to buy gifts when they can't afford to, or even if they can afford it but choose to support the school or teachers in other ways.
Some of the best "teacher gifts" I've ever received have been small, craft-type items, handmade by a child with help from a parent, and I appreciate a $10 Starbucks gift card as much as a gift of a 1 hour massage. The best gift is knowing that parents appreciate us for loving, teaching, and caring for their children.