Half-ounce fragrance oils. Summer sampler now available in my bath and body supply store.
You can use both fragrance oils and essential oils to scent your products, but there are some big differences between them. Here are the basics for beginners - this is just an overview article, nothing in-depth.
Essential Oils are concentrated, distilled plant essences from a single source. They have plant properties and have been used in natural medicine for years. Here's the thing - many essential oils smell great (lavender, for instance), but many of them smell really medicinal and funky out of the bottle. Not all of them are even appropriate for use on the skin, so it takes a little research to figure out what to use.
In fact, some essential oils are downright irritating to the skin and lungs. I remember making a room spray with cinnamon essential oil... AT-CHOO! It was like tear gas, oops!
If you use essential oils, be careful. If you're a beginner, get a good book on essential oils before you start. There are many great essential oil references out there, and I would suggest buying a book rather than looking online. Websites come and go, and you can't believe everything you read on the internet, especially about health and skincare!
Fragrance oils are (often) a blend of natural and synthetic components. They have a reputation of being cheap, synthetic substitutes for natural ingredients. Fragrance oils are certainly less expensive than essentials, and most of them contain lab-made fragrance components; however, this doesn't mean that they smell bad - quite the opposite!
Bad, low-quality fragrance oils smell bad. But good fragrance oils are what's used throughout the bath and body industry. Fragrance oils aren't all synthetic, either, most of them are a blend of lab-made components and essential oils.
One big benefit to using fragrance oils is that they are skin-safe when formulated for bath and body use (not candles.) They're meant to be used on the skin at proper dilution, so you don't have to know anything about them to use them.
Also: if you love berry or fruit fragrances, you will have to use fragrance oils - there's no such thing as apple or strawberry essential oil! You just can't get aromatic components from many fruits, but you can synthesize them well.
If someone says they have "fragrance allergies," usually they have no idea what they're actually allergic to. It could be the "fragrance"... but which component? Fragrance oils are a blend made of 10's - if not 100's - of natural and synthetic ingredients! It could also be anything else in the skin products that they use.
Essential oils trigger just as many allergies as fragrance oils, so there's no foolproof way to avoid allergies altogether. It's possible to be allergic or sensitive to anything.
It really depends on what you're after. Essential oils can do wonderful things for your skin, if used properly, but you have to put in some research and development. Fragrance oils are a lot easier to start with; you can jump right in for instant gratification. I don't know anything about the medicinal properties of essential oils, so when I use them, I always stick with "safer" ones such as lavender, chamomile, rosemary, and bergamot.
As always, I hope this helps! - Cat.