While I like the easy to use kit with the exact amounts of needed color and peroxide in separate bottles, the cost is way out of line for the convenience. An eSalon coloring 'kit' costs $20, and shipping is another $6.
So you're paying $26 for a one-use root touch up. At the same time, a bottle of hair coloring from nationwide Sally's Beauty Supply costs less than five dollars, and the necessary bottle of peroxide is just $2. So customers pay $26 at eSalon, and less than $7 at Sally's.
I've communicated with eSalon about their excessive shipping charges, and been told that if I order two kits at the same time, one will be shipped free.
That's just a gimmick. Even the Post Office says that it doesn't cost $6 to mail such a lightweight package, and businesses actually get a mailing discount.
Be aware of the high (and for them, profitable) shipping costs before considering ordering from eSalon, though I admit their product is superb and doesn't fade, though it really dries out your hair, meaning you have to buy special moisturizer to undo the damage.