I have seen a disturbing trend in craft stores lately. In the soap making aisles I have seen little bottles labeled as essential oils and when I look at the prices I know they can't be. I think there is way too much confusion over what an essential oil is and what aromatherapy is.
Essential oils are extracted from plants, usually by steam distillation. Citrus oils are usually pressed from the peels. Some oils are extracted with solvents and would correctly be labeled as absolutes and not essential oils. This method is used with flowers like Jasmine (that can't survive the steaming process) or sometimes Roses (they have a very low oil content and more oil can be extracted this way). Some oils, like Rose or Lavender may be found as a pure essential oil or as an absolute. The pure essential oils are used for therapeutic purposes while the absolutes are best suited for perfumery. The differences in oil content in a given plant is reflected in the price of the essential oil. Citrus oils are plentiful and easily extracted and are dirt cheap, like say $5 an oz. Lavender flowers have a high oil content so steam distillation produces plenty of oil. You can buy good quality Lavender for $15-$20 an oz. It takes, literally, TONS of roses to produce 1 lb. of Rose essential oil. For pure steam distilled rose oil you could easily pay $1200 an oz. So if you see Jasmine or Rose "essential" oil selling for $5.00 for 1/2 oz. bottle-don't waste your money. These are fragrance oils.
Aromatherapy is the use of these aromatic oils for therapeutic purposes. Just because something smells good doesn't make it aromatherapy. If you want proof take a whiff of some Valerian root essential oil. It does NOT smell good but is a wonderful oil. I know some commercial products are starting to add essential oils to their products but they also use artificial fragrance oils that contain man made chemicals. So what's the point? The only point is to attract the business of a public that doesn't know any better.
Should you decide to try out true aromatherapy for yourself, there are some important things you need to know. Buy quality oils from a reputable supplier. I like Mountain Rose Herbs, Camden Grey, and Aura Cacia. Some people like NOW but I have issues with them (see their Jasmine oil and you'll know why). Learn how to use each oil that you buy. A few oils can used undiluted (Lavender, Tea tree) on the skin while others (Cinnamon bark) should never be used on the skin at all. Lavender should be the first oil you buy and the one oil you should always have in the house. It is miraculous on burns and wounds, zits, in the bath, in a diffuser, in skin care oils, etc. For first aid it speeds healing and prevents scarring. A drop applied to a fresh mosquito bite will almost completely eliminate swelling and itching. A drop massaged over the forehead, temples, and back of the neck will cure a tension headache. It balances the mood, regenerates skin cells, eases tension, promotes restful sleep. In a bath you can add 4 or 5 drops to bathwater after it has been run, swirl it around and jump in the tub. RELAX. The essential oil enters your body through the nose and the skin and your blood stream circulates throughout your body.
This is my beginners advice for aromatherapy. There are a lot of wonderful resources on the net so self-study isn't difficult. Comment and I'll be happy to answer any questions.