it seems like a no-brainer to me (and you) that they would see the value in buying in bulk. I guarantee they’ve bought a carton of cigs before. Perhaps equate the 120 ml to a carton?
What if you rolled in the value of their time into that equation too?
"Not only do you save 50 cents per ML with the larger bottle, but you’ll free up time by not having to come in here every X number of days. How much is your time worth to you?
The one thing about time is, it doesn’t replenish. But your money gets replenished every 2 weeks. "