Need to be able to send a customer a link with a prebuilt cart + coupon attached - All ready to go

[BradGrillRescue]

Hey there,

I'm trying to find a solution (app or not) where we can send a customer a link or button to click that brings them to a pre-build cart with a discount code applied so all they have to do is purchase.

We want to cut down on the time it would take a customer to go from our recommendation to purchasing that recommendation.

Situation: 

Customer is contacting us going back and forth via email and they're on the fence about purchases Product A with upsell of Product B.  

We discuss the benefits and say "hey, if you wanted to purchase now, I can give you X% off.  Click this link to the cart already set up for you and the discount code applied"

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We want remove the obstacles that could arise if we just hand out a code and want the customer to build their cart and add the code themselves.

Does anyone have a good solution for this?  I might be not looking under the right search terms in the app store.