[solved] Free delivery if minimum purchase reached - otherwise elastic delivery fee applies

[sunnyb0y]

Hello,

 

I am building a PrestaShop (1.5.4) site for a region specific fruit and veg delivery business.

 

We want to have free delivery if the minimum purchase is reached ($15).

 

Otherwise a delivery fee will apply - the client would like an elastic delivery fee that adjusts relative to the products in the cart so the minimum purchase is always $15.

 

Eg so for orders under $15, the purchase amount plus the delivery fee should always equal $15

 

Example 1: Say there are carrots, potatoes, nuts and flowers in the cart with a sub total of $11. The delivery fee should be $4. This makes a total of $15

 

Example 2: Say there are apples and onions in the cart with a sub total of $7. The delivery fee should be $8. This makes a total of $15

 

Example 3: There are many items in the cart with a sub total of $25. The delivery is free. This makes a total of $25

 

How do I set this up in PrestaShop?

 

I have set the minimum purchase price of $15 in the Shipping > Shipping section but not sure how to do the elastic fee if the purchase is under $15.

 

Any ideas?

 

Thanks in advance.

Edited August 15, 2013 by sunnyb0y (see edit history)

[sunnyb0y]

Solved - sort of...

 

Not totally elastic but a good compromise has been achieved using the "Localized Shipping" module and a price scale like so:

order total of 0.00-1.00 = 15.00 delivery

order total of 1.00-2.00 = 14.00 delivery

order total of 2.00-3.00 = 13.00 delivery

etc

order total of 15.00-1000000 = 0.00 delivery

 

This works well for our purposes.