Selling essential oils too

Besides making and selling soap, I also sell all the supplies that are used in making soap and lotions.  Having sold essential oils for years from my store, I've noticed something that is interesting about people's perception of size.  When people see little bottles, they just see a little bottle, be it 2 oz or 1/6th an oz (30 ml or 5 ml).   So, for example, if you were to sell a 2 oz bottle of Lavender essential oil at $20, people will think that you are overcharging because they will remember seeing a 'little bottle' of same essential oil for approximately $10 at the health food store.  Yet, that health food store bottle is 1/3 oz (10 ml), measuring one sixth of that 2 oz bottle.  Math wise, this means that to get the equal amount of Lavender essential oil from the health food store, it would cost you $60. 

Those little 1/6 oz bottles are very small, but the 1/3 oz and 1/2 oz bottles don't look too different is size, and those are almost as tall as the 1 oz.  So I have started selling 1/6th oz bottles of essential oils, and these sell very well at the $4.50 - $5.50 price range.