I use only therapeutic grade EO, specifically Young Living.
I have had good experience with them healing asthma, reaction to anesthesia, etc.
Over the years I bought many oils, slowly. As a distributor, when I order oils for my friends and share shipping, I save on the prices too, because when you meet that month's PV, you get almost 50% in free oils!
I don't have all the oils yet, but I discovered that some oils are "must haves", so I always have those. Many times I buy mixes, which already have expensive oils in them, like Rose, only for a fraction of the cost.