Create Bulk Bottle Deposit/ Service Fee Attribute
Go to Items.
Press Custom Attributes in the upper right corner.
Press + New Custom Attribute.
Under ATTRIBUTE CODE, enter container_number_of_items.
Under ATTRIBUTE NAME, enter # of Items in Pack (or whatever is relevant and obvious).
Under CUSTOM ATTRIBUTE TYPE, select Product attribute / string.
Under FRONTEND INPUT TYPE, select Select.
Under SELECT VALUES, press + Add New.
Under VALUE enter 1 and under LABEL, enter 1.
Press +Add New. and continue adding necessary values. So if you sell 6 packs of sodas, make sure to include VALUE 6 and LABEL 6.
Under UI COLUMN SIZE IN POS, enter 3.
Scroll down and press Save Changes.
Go to Items.
Locate the item you want to assign a bulk bottle deposit/service fee to.
Press the edit icon to the right of it.
Under # of Items in Pack, select the number of items associated with that product. If it is a 6-pack of soda select 6 and if it is a 24-pack of beer select 24, etc.
Scroll down and press Save.