A lot goes into the calculation of "worth buying". 100 ml. Velvet Vapors eliquid is 39.00, USPS shipping 3.87. 125 ml. eliquid is 19.95 from EC, and 20 percent off that with their discount code, free shipping for orders 130.00 or more. So it depends on what you're stocking up on, liquids, batteries, bottles, needle caps, etc., and how much. I tend to order there when I'm running low on LDPE bottles w/ needle tip caps because I can't stand trying to fill a glassomizer from those unicorn tip bottles so many sellers use. I get double strength, mix it down with pure pg and funnel it into bottles I can put the needle caps on.
Anyway, you get my point.