There are entire blogs dedicated to essential oils alone, but don't get bogged down by the complexities. You only need a few tried and true favorites to get started.
Whether you diffuse your oils or add them to DIY cleaning products, you will be well on your way to becoming an oil mama with these essential oil essentials.
5 Essential Oils
Oil Diffuser
Saje and Vitruvi both make beautiful diffusers. (And despite what they say, you can absolutely diffuse other brands' oils in these diffusers.)
Lovely Essential Oil Brands
All of these brands except Saje are available on Amazon.
There are also dozens of other essential oil brands that are perfectly lovely. Although certain brands will claim otherwise, most high-quality essential oils are created more or less equally. If you can get it at Whole Foods or your favorite local hippie food store, the brand is probably legit. Just do your homework online to learn more.
Hope that helps get you over the oily hump!