Its all about profit margin. If a company charges 250% of their production cost for a liquid, and doesn't charge shipping, it's of little significance in comparison to a company that charges 150% of their production cost for a liquid and does charge shipping.
I'd recommend not caring about shipping as much as the 'total' after shipping (or lackthereof). Example - 20$ for 30mls of liquid (no shipping cost) vs 27$ for 90mls liquid (plus shipping). I'd rather pay shipping.