Depends on the year, and how our budget is. We usually buy for parents, nieces & nephews. Extended family, aunts & uncles etc don't generally buy for other adults.
Usually it's $20-30 each person, although I seem to end up adding bits & pieces here & there.
Buying for each other...sometimes. DH is hopeless because he never wants anything, he is so very hard to buy for. This week I have picked up my easel I have been waiting for weeks & weeks for (since my birthday!), so that is my christmas present