I am launching a new store selling one product. I want to run a "you buy one, I donate one" campaign to donate to Essential Workers during this crazy time. In order to offset a small portion of the cost, I want to create a bundle which is slightly more expensive, but draws from the same inventory sku. I have tried different variants and an upselling app to create an add-on. I am getting stuck on the inventory. I have only one product, so I need to use the same sku number, but with different pricing.