If you love professionally arranged evergreen centerpieces that look and smell like Christmas, why not mix some of your holly leaves with other branches from your yard? You can experiment with different types of evergreens (cedar, juniper, pine, etc, each has a unique texture, smell, and color) to find a look you like. Construct a low centerpiece and you have a table decoration. Construct a tall centerpiece and you have a beautiful mantel adornment. Or, place a vase with greens, like the one pictured, in any room of your house for a little holiday cheer that is simple, understated, and personal, especially when entertaining guests.
Other naturally derived decorations include pinecones in all shapes and sizes (if you collect any in the fall that seem sticky with pitch, bake in the oven at a low temperature for 20 minutes or so and the pitch will melt, harden, and shine as the pine cone cools down), acorns (always chose those free from worms and/or worm holes), dried grass blooms and other dried blossoms like hydrangea. I've also been known to hang sea shells and cinnamon sticks from the Christmas tree in addition to pinecones. If money is in short supply but the desire to decorate for the holidays is not, it's worth looking outside for inspiration.