Stacks in redback have been designed to allow e-commerce store owners to quickly create simple bundle deals where users can buy multiple products with one button click and can (optionally) receive a discount on one or more of the contained products.


Possible scenarios available with the stacks feature:

buy one, get one free (2 items in a stack with 100% off one of the items)

buy one, get one half-price (2 items in a stack with 50% off one of the items)

buy two, get both half-price (also available as a discount code) (2 items in a stack with 50% off each of the items)

buy X get Y% off (X items in the stack, each have Y% off)

buy X get Y% off a specific item (X items in the stack, one has Y% off)

buy 2 get 5% off item 1, 10% of item 2 (2 items in the stack, one has 5% off, one has 10% off)

buy 6 get 1, 2, 3, 4, 5, 6% off respectively (6 items in stack, 1% off item1, 2% off item2, 3% off item3, etc)


Stack items explained:

in order to buy a stack, the system has to know which products the user wants to choose. this is done with dropdown boxes on the stack page, alowing the user to select the items they would like.


an item in a stack is one of:

  • a product-option
  • a product
  • a product-group

a product-option is a line which appears in admin > shop > products > product-options 

[in most e-commerce stores this is the same as a product] - uses include sizes of clothes (eg small, medium, large)


a product is all product-options from a product in admin > shop > products

[in most e-commerce stores this is the same as a product-option as most stores set one option per product] 


a product-group is all product-options from all products in the group - admin > shop > product > product groups

for example if your products are "sizes of boots" and they are grouped together then the product group option will show each of the sizes of the boots



creating stacks:

login to your redback admin

go to shop > stacks

click add new (or click an existing stack to edit)

fill in details

the price and RRP boxes are not used if your site auto-calculates the stack totals


in the stack-products tab search for a product

you can use the 'options' dropdown in the results to select a specific option

click add to add the product to the stack

repeat for all products in the stack


once all products are added, you can set the options and discounts for the products included in the stack at the top of this area


in the frontend, next to the buy buttons are some dropdown boxes which allow the customer to select which product they require

- eg 'pick from one of these two products and get a free item'


the dropdown for 'option' will change which item is shown by default in the front-end

the dropdown for group will determine which group to show for the user to select between, if the product is in more than one group


the Item Type dropdown determines what to show in the main dropdown for the user

- product and all options will allow a choice between each item from the 'shop > products > product > product options tab'

- selected option only will allow no choice, and will show the item selected in the dropdown for 'option' on the left

- all products in group will allow a selection between everything in the group (shop > products > product > groups >)


discount type can be set to 'none' or discount value (without a percentage symbol)

- none will add the product at its current price to the stack

- percentage will reduce the item by the specified percentage - the percentage discount to add is input in the box below

- fixed price will reduce the item by the specified value - the discount to add is input in the box below


you can combine percentage and fixed price discounts (eg item 1 has 10% off, item 2 has £10 off, item 3 has no discount)


for fixed value discounts, the discount value (eg £5) is removed form the final price of the item (the price INC VAT)


this means that is an item is

8.33 ex vat

10 inc vat


and you want a discount of £5 then it becomes

4.16 ex vat

5 inc vat



** Stacks will show as out of stock if any of the items in the stack are out of stock (the back-order functionality is not available in stacks)


for example, to set a stack that allow the customer to pick from one of these two tshirts and get a free red cap you would:

1) goto admin > shop > stacks > add new

2) search for tshirt

3) click add

4) search for cap

5) click add

6) in the dropdown for 'itemtype' for the tshirt product, select 'all products in group'

7) in the dropdown for 'itemtype' for the cap, select 'selected option only'

8) in the dropdown for 'option' for the cap, select the red version

9) in the dropdown for 'discount type' for the cap, select 'discount value'

10) in the 'discount value' box, enter 100

11) click save




limitations in stacks:


as with any system the stacks feature has limitations:

its designed purpose is as above - ie that it has been designed to allow users to quickly add multiple products with one button click


depending on the type of promotion that you wish to run, you may need to use an alternative feature in your Redback System, or perhaps a bespoke feature may need to be developed to your specification.