Scented candles make up an estimated 75 to 80 percent of all candles sold in the United States, according to the National Candle Association.  Tealight candles, votive candles, and jar candles are usually the most popular types of scented candles.  Some people may be allergic to certain fragrances used in candles, so it is important for those people to avoid those scents.  However, many people enjoy scented candles, so a candle in their favorite scent is a great gift idea.  Candles should always be burned in well-ventilated areas.