I think you do what you can - just like with everybody else. This year my family is doing a "no-cost" gift exchange because all of us are strapped for cash - for all different reasons, but it's really nice that it's all the same year!
As for the sitter - do you know of something that she really likes? For instance if Tammi or Erika were my sitter I might get them a gift certificate for Dunken Donut's coffee.

Something that you've noticed that she likes, that isn't super expensive, but is thoughtful. I like the idea of something for the daycare center, too - such as a big toy that the kids could play with.
ETA: I will miss Kurt's bonus this year - he used to get a whole MONTH'S pay. We had really nice Christmas mornings... but being a teacher, he obviously doesn't get a monetary bonus this year - but he does get a month off of work!