I'll be the first to admit, I'm not really well versed in oils at all. The most I've used is eucalyptus oil in the laundry to fend off dust mites and some lemon oil mixed with vinegar when cleaning. I have done some reading up on the subject though and it's clear that there are different standards and processes when it comes to oils and the price can vary greatly.
Native American Nutritionals seems to have a good reputation, and they provided me with some additional resources and eczema remedies in the following link:
Let me know if you try any and how they worked!