Scented Oils

I am in need of a good resource for scented oils that have not been diluted. I am making gifts for Christmas and some will be scented, like eye pillows. I cannot use regular perfumes at all due to the alcohol in them (and the scent fades). I have purchased oils from different local businesses and the *same* oils are noticeably different. Some are much "cleaner" and fresh than the others so I suspect some businesses are diluting their oils with something. The best oils I've purchased still smell great after many years. For now I am interested in scents such as Lavender, China Musk, Vanilla, Frangipani, etc. I can purchase them in small quantities locally but it is expensive.

Thanks for any ideas you have!

MJ