Hello. I'm converting my store over to Shopify and I'd like to find an App that would allow customers to select the qty of the add on items, while still leaving the base item as a qty of "1". My current site allows them to select the add-ons with a checkbox, but they can only purchase one of each.
For instance, in the image below the customer may want to purchase (1) gallon of the main product, but (3) of the add-on aerosol cans.
Any help would be greatly appreciated.
So for original item X, you need a bunch of discounted items W, Y and Z, that are not variants of X (i.e. are completely different things) that have the following characteristics:
1. Show up on the same page as original item X
2. Be discounted, if bought alongside the original item X
3. Are available for multiples pruchase, i.e. you can buy more than one of each of W, Y and Z (sorry for the clumsy phrasing)
So for the first part, you need to use the recommendations object - https://www.shopify.com/partners/blog/related-products. A good apps that does that is Wiser - https://apps.shopify.com/recommended-products-wiser. If you'd like to go it alone you can also hack something like https://gist.github.com/carolineschnapp/1002801.
The second and third requirements, however, are (as far as I know) not satisfied by Wiser. For that you'd need an Upsell app.
A good one is https://apps.shopify.com/discounted-upsells, which takes care of 2, might or might not take care of 3 (I'm sure you can buy a single item for the discounted upsell, not sure if you can specify multiples). But, it does not take care of 1 - it does not allow you to upsell related products on the same page.
Give these two a spin. If you're still stuck and are determined to have the exact same look and feel, ping me back here and we can see what I can do about it. Whipping an app that allows you to create those extra products is not difficult, but I wouldn't rust to build it if the need is satisfied by one of the major apps out there (which BoosterApp's Upsell definitely is).