buy a 6 mg and a zero mg of the same flavor...mix equal parts and you end up with 3mg.
or at Gourmet Vapors you can get double flavor added for under $1.00 more
(on the 10ml-15ml-30ml bottles).
So you can buy one 6 mg double flavor 30ml bottle
divide it equally into two different bottles (15ml in each)
add 15ml of either PG/VG (or a combination to make 15ml) to each bottle
you get two 30ml 3mg bottles of ejuice for a lot less $ !