Lately I've been researching hydrosols- water that has been used to distill a plant for its essential oil. While they are usually a byproduct of essential oil distillation, sometimes the distillation is done specifically for creating the hydrosol. They are often cheaper than the essential oil, perhaps always, but I haven't looked too much into it yet. The scent is lighter, and often quite different than the fragrance of the essential oil.
Witch hazel is one of the most common hydrosols, and you can often find it at your drugstore, mixed with 14% alcohol as a preservative. You can sometimes find rose or orange blossom waters in the baking section.
The problem with hydrosols is that since they do contain water, they can go bad. If you're buying small amounts for personal use, it's probably safe to keep it in your refrigerator and use them quickly.While looking into hydrosols, I also started looking into preservatives, since I wouldn't want to sell anything that could go bad easily. While I didn't want to use preservatives in my products at first, after doing some research, I've found some that I would be comfortable using in my products. If the tests turn out well, I might have some hydrosol products available for sale soon. There is also alcohol- a good amount of high proof alcohol also acts as a preservative (see witch hazel, above).
I have bought several small bottles of hydrosols, and while I plan on moving forward with using some of them, others were not so appealing. Yarrow is almost gag-inducing. There are also some fruit hydrosols out there, which can be used to create natural fragrances with strawberry, apple, and other fruity scents.