I'm just going to list things off the top of my head right now and probably come back later to the thread.
We strive for simple holiday decor. I find inspiration from Colonial/ rustic decor. My front door will be decorated w/ a burlap cone filled w/ evergreen, holly, and pine boughs from my yard and neighborhood. I also put the boughs around the house as decor. My table centerpiece will probably be a bowl of fruit pomanders the kids and I make for the season w/ oranges and cloves, hand me down candleholders, and beeswax candles we roll ourselves. We cut our tree from a farm and the decorations are mostly homemade; we add at least 1 new type of handmade ornament a year. This year I think we're stringing popcorn and cranberries. A couple rolls of holiday ribbon from Target goes a long way for us and is reused every year (bought them in 2003). A couple baskets filled w/ pinecones and a candle warmer w/ a mason jar of water, cinnamon sticks, cloves, peppermint, and citrus peels and I call it done.
For gifts, I try to stick w/ consumable or practical. This yr my kids are getting 18oz klean kanteens w/ a felted water bottle carrier I knit for them. I'm also making them each a rag quilt for added warmth on their beds, and knitting each a wool hat. They'll each be getting 1 store bought present (DH's insistence), probably Playmobil or Lego sets. I try to stick w/ mostly handmade for extended family, too. Knit socks, fingerless mitts, knit hats w/ funky designs. Last year for the grandparents, my kids made tea light jars. We took baby food jars(collected from one of DH's coworkers who had a baby), watered down glue, and red and green tissue paper (I save tissue paper from gifts). Tore up the tissue into pieces and decorated the jars. Put homemade beeswax tealights in and done. Grandparents loved them and they were so simple.
We strive for more experiences than "stuff". I think we'll be "elf-ing" neighbors this year w/ homemade candles or goodies, we try to go look at Christmas lights around, we went caroling last year w/ our church's youth group, we helped pack Salvation Army food boxes, and this year we're going to do Operation Christmas Child through our church. Some of these may not be "frugal" b/c they cost us some money, but they're teaching our kids service, giving, and compassion to others who are struggling or not as fortunate as we have been.