Make your own gifts.
This isn't possible for everyone on your list most likely, but for those you can? Do! This year I made Socktopuses for my younger nieces (which they all seemed to like!), homemade liquid hand or dish soap for a variety of friends, and I also plan on making some body scrub (probably like the scrub I made here) for others. For my sisters and their husbands I made Andes Mint Fudge and No-Bake Oreo Truffles (which I can say here because we already "did Christmas" with my side of the family!).
Shop at dollar stores!
For much younger children, a dollar store can be a great source of fun but inexpensive toys and personal care items (toothbrushes, fun wash cloths, hair clips, brushes, etc). They can also be helpful when attempting to fill stockings for older kids or even adults (again, toothbrushes, combs, small candles, clip-on booklights etc).
Don't go overboard with the food.
I know the holidays are considered by most to be a time for constant feasting but trust me; you'll enjoy those cinnamon rolls on Christmas morning a lot more if you haven't been living on junk for for the entire month already! Pick a few special items to have through the season and make them last! Sure, 10 cookies in one setting taste yummy, but your budget and waistline will thank you for stopping at 2 or 3 instead.
Reuse and recycle!
There's no need to spend a TON of money to make your home look cheery this holiday season. All the latest lights and decorations simply aren't necessary. Instead consider decorating with things like paper snowflakes (a great project to do with your kids; everyone will have a great time and there's something even more special about hanging decorations you made with your own hands!), or turn an old tomato cage upside down, wrap it in lights, and viola! You have a perfect lighted tree for your home or yard for the cost of a string (or two) of lights instead of $20+ for the "real deal". Also consider making your own ornaments, using old T-shirts in holiday colors, cutting into whatever shape you desire and stuffing them with cotton balls and gluing together with fabric glue, or making cut-out ornaments with applesauce and cinnamon (which happen to pull triple duty; great holiday project with the kids, fun gift to give, or beautiful on your own Christmas tree!). Also consider bundling up and taking a nature walk with the kids. Gather up sticks, pine cones, etc., paint with a thin coat of watered down Elmer's glue and dust lightly with some white glitter. Once dry, place together in a pretty bowl for a simple holiday centerpiece!
Here's a photo of our tree and mantle area -- all these items (including most of the ornaments!) were either bought after Christmas at seriously reduced prices (think 75+% off!), were hand-me-downs, or gifts. Even the tree was purchased several years before I married David for something like 80% off the original price!