I'm an adult child
We've asked my husband's parents to give us nothing, just shop for the grandkids. My parents give us all a new pair of pjs and then spoil the kids. Usually I say "nothing" when my mom asks what I'd like, but this year I asked for a Soda Stream.
As for my boys, they are little and still believe. I'm guessing I spend a few hundred on each one. They are each getting two Lego sets, a board game, a craft set, and some Star Wars figurines. The little one is getting a Kindle and the big one is getting an air hockey table.