If they plan to wake up early to shop online and try to get some things for me, I would do it. I would also do it if the person usually doesn't ask for favors and just wants one or two things.
I have already announced that I will be doing my own shopping and they will have to get whatever they need themselves. Several people begged me to get popular things in the past, even to stores I wasn't planning on going to, and I have done it for them. This year, no one wants to watch the baby for me so they can just do it themselves!