Unrelated to a specific challenge and I know the answer is here somewhere, I just can't remember. It's been like 3 years since I completed challenges so I really no longer remember...
When are the coupons sent out for the challenge rewards and how long are they valid for? I remember something about the first or second full week and valid through that week or something but its been way too long. I need to plan my budget better so I have to be aware of such things.