Coupon codes are not compatible with our product reimbursement process. We have no way of preventing influencers from using the coupon code themselves, so we're unable to allow use of coupon codes.
If you do not care if some influencers use coupon codes for their purchases and lose a bit of money in reimbursements than we can suggest influencers use a coupon code to incentivize traffic to an e-commerce platform. However keep in mind that not every influencer will include a code in their posts since some prefer to be more authentic with their testimonials.