I have a question as to whether the functuionality exists in Magento for the following:
I want to apply a discount to all products from the same vendor. However, I want to additionally apply an option for the shopper to decide whether to take the discount in its entirety or to rather pass that saving as a donation to a non-profit charity.
Can I add a selectable option at checkout for them to choose the charity and manually apply the amount they want to pass on to said charity?
This isn't in Magento by default. You will need an extension that adds this function.
I would possibly scope it so that on the checkout page the extension sums the total cost of the items from said vendor. It then would ask you to choose a charity from the list and move a slider from 0-100% of the % amount you will take as a discount or give as a charitable donation. Depending on where the slider is it would apply the discount amount to the order and save the charity amount to a report for you to access.
Do you have a developer to help with this kinda stuff?