A lot depends on your typical monthly budget and who you shop for. Our family has scaled back from gift giving for adults. We might pick up a little something for everyone, but it's not a ton. Maybe $100 for all the adults. I mostly send everyone printed pictures of our children. That is somewhat cheap at Christmas time, but we spend a lot of money on professional pictures throughout the year.
We shop mostly for the children, so I try to buy toys as I see them on sale. Our daughter already has some stocking stuffer princess toys, a Mr. Potato Head, as well as a bunch of books that she's not quite ready for and a big puzzle that she can't play yet but was $3 in the target dollar section. So far I've spent about $25-30 for all the toys since January. The other thing I do which works well for young kids is to wrap almost everything. It makes the tree more "magical" and exciting. My daughter literally unwraps boxes of chalk and I'll wrap up the $3 puzzle. So that's $5 for two presents under the tree. We do end up spending a little more on wrapping paper that way, but I know she will always remember how the tree was so full of presents.
Make your grocery meal plan early and the traditional dinner foods will go on sale in the weeks between the very end of November through December and there are coupons that whole time as well. So one week it might be fried onions, condensed milk and stuffing and the next week canned corn, gravy, sweet potatoes. If you already know what you are going to want, you can buy the non perishable items throughout the month on the week they are on sale. I save at least $10-$15 buying sides when they are on sale and using coupons.
We also don't budget any cash into our savings account in December and use whatever we want for family memories, presents, food, etc and just throw whatever is left over at the end into savings.
Here's a good resource from FlyLady:
http://www.flylady.net/c/holidaycruise.php
