Buy an oil burner and some essential oil - exactly as you’ve said - you can get cinnamon, orange, clove, lemon, pine. Literally a couple of drops in the burner with water will last hours and fill the room. You can blend your own and experiment with one drop of one thing and another of another, etc. Loads cheaper than candles, my essential oil bottles have lasted 3 christmases now. There are a couple of very reasonable and reliable pure oil sellers on eBay I’ll look at the name on the labels when I get home if you want?