3 for set price promo - how would I set this up?

[MDJO]

How would I best set this type of promotion up?
I have some dog treats that retail singularly at 40p and Iwant to do a “3 for £1” offer
I have set up a promotion in Discount Manager based on “DefineQuantity Based threshold” , with a threshold type of Units (buy 3) and discounttype of value (£1 instead of £1.20)
I have assigned the promotion to the single SKU in question
It’s thresholds I’m struggling with
Do I put in thresholds
From (Units) 1 tounits (1) = £0 discount
From (Units) 2 tounits (2) = £0 discount
From (Units) 3 tounits (3) = £0.0667 discount
From (Units) 4 tounits (4) = £0 discount
From (units) 5 tounits (5) = £0 discount
From (units) 6 tounits (6) = £0.0667 discount
Etc
If someone buys 3 or 6 units I can see that they wouldachieve the discount, however what if they buy 4 units ? Will the £0 discount apply to all 4 units?
Ideally it needs to apply a discount for the first three andno discount to the fourth
Does anyone have any suggestions how this may be best setup?
Thanks if you can help

[MDJO]

Just had another thought… should the discount be set at 6.7p(ie the discount per sku) or the total discount i.e. 20p?

[MDJO]

It's OK - I have sorted it out
It's 1 to 1 = nil disc
2 to 2 = nil disc
3 to 3 = 20p disc
4 to 4 = 20p disc
5 to 5 = 20p disc
6 to 6 = 40p disc
etc