You're not exactly buying a gadget or a meal, and you're not buying training from a for-profit company. What you're buying is the right to be able to take the PMP exam provided you are eligible. I don't see PMI offering coupon codes for their PMP exam not in a million years and here's why:
- There is no benefit for them whatsoever
- Over 90% of the PMP applicants are reimbursed the price of the PMP application by their company (regardless if they passed or failed). 90% of the remaining 10% don't care if there are coupons or not
- PMI already offers special pricing for members. For a small fee you can be a PMI member and save on the PMP exam (it'll cost you less to become a PMI member and pay for the exam than just paying the exam if you're a non PMI member)
A word of advice: As a project manager, you shouldn't be cheap on yourself, especially when it comes to education.