My first dive into the oil world was with the Suki Face Pure Facial Moisture + Balance, which consists of blue chamomile and echinacea. I like to use this one when I have any redness or signs of breakouts because of the ingredients' anti-inflammatory properties. My currently most-used is Aura Cacia Rosehip Oil. It's incredibly affordable when purchased at a health foods store (I picked mine up at Whole Foods). Rosehip Oil is said to be good at reducing acne scars, which is my current skincare concern. For general hydration, Josie Maran Argan Oil Light and tarte Pure Maracuja Oil are good picks.
I apply a facial oil as the last step of my evening routine, after cleansing and toning. You can also follow it up with an additional moisturizer, but I find that all the above facial oils are hydrating enough for my skin. I really don't subscribe to the normal/oily/combo skin type methodology and am more focused on my current skin concerns when choosing a product whether to purchase or to use that night. If you haven't tried a facial oil yet, I highly recommend it. I feel quite fancy with my little glass bottles applying it at night and wake up with glowy, fresh-looking skin in the morning.
Do you use facial oils? Any favourites?