Discount Gives and Gets

Let's say you're working a deal and you've maxed out the discount you can give the client without having to go to deal-desk or RevOps for additional approval. They tell you "well, if you can get me 15% I will sign today"...but the deal is already so packed with incentives that you know you'll be denied unless you have a solid "get" from the prospect that shows good-will to the approval team. What do you "get" from the prospect in this case?

Do you go for a multi-year deal to bolster the margins?

Do you get referrals?

Do you get a customer story?

Do you get them to participate in your customer advisory board?

There are so many options out there, but what's your favorite?