A mate of mine's consulting company offers a 10% discount on any work if the client buys them a plant, any plant, for the office. Apparently they've only had two clients take them up on the offer.
Discounts after the contract is approved are actually a headache in some large orgs. You will have to answer multiple questions each quarter as to why your numbers are off. You won't get to spend the money elsewhere, but will have more work. Plus, you'll never get budget approval for buying or shipping a plant.
Plus, if the budget has already been approved, someone didn't read the contract before signing it. That's the same as not reading it.
I want the future back, we were promised hoverboards!