And speaking of buying food on the cheap, don't hesitate to stock up on store brand items. After all, by the time guests start arriving, chances are good all the boxes and cans that the products came in will have long since hit the trash, so even if you have a few snooty guests with the spare cash to indulge exclusively in name brand cuisine, they won't be able to tell the difference.
Bulk food is another good money saver -- especially since you don't want to run out of anything essential after the stores shut down for the holiday. For ingredients that don't feature strongly in your regular menu, you might want to back off from buying in bulk. If the item is a holiday staple or is something that pops up in your recipes on a regular basis, it can't hurt to stock up.
Don't forget to compare different types of the same products, too. How do the canned tomatoes stack up to the fresh ones? How about the sweet potatoes or the ingredients you need for a casserole? By comparing serving sizes across aisles, you can scoop up additional deals.