“Luxury” is subjective. I consider Castor Oil to be a base oil...and at 5% it’s not expensive. Like many soapers, I tried a lot of different oils and butters and finally settled on Olive, Coconut, Palm and Castor Oils, and Cocoa and Shea Butter in my regular soap. Considering that I’m still buying my supplies in 1 lb and 7 lbs quantities, my ingredient costs for a regular unscented bar is $1.07. EOs and FOs are actually my most expensive ingredient and can add $0.60 to $1.25 to a bar. I am looking at making a ‘luxury’ soap...something decadent, fancy box, fancy shape, limited edition. But in the end, it’s still soap.