@Ana1234 - I was very interested in aromatherapy for a long time and I picked up all sorts of little bits and pieces about how you can use it in crafts. If you really like the candles, it might be cheaper to make them yourself. Aromatherapy essential oils tend to be expensive also, but they last for a while since they are incredibly strong.
So strong, in fact, that you have to be careful not to put them directly on your skin unless you're sure it's safe, or they've been diluted properly. Don't put pure peppermint oil on your skin, for example or you will regret it. You can dilute it with base oils or water, although if you're going to do it with water remember to shake up the bottle before using it, as the oil will separate and drift to the top. And use a spray bottle so it won't end up concentrated.