The entire coupon process has become too full of variables and exemptions. Coupons may or may not be viable on sales items, but never when the items in the sale are given the Prime Flash sale tabs, except that when it's a BLUE Prime tag item, then the coupon MAY work. And then PAs may independently chose to honor or not honor coupons, or in the case when there are coupons that aren't usable on sale items, instead run a much smaller 'sale' in order to circumvent the higher discount. Not to mention that coupons aren't usable on clearance items, even though clearance items are already exempt from most sales, so the net effect is to make clearance items LESS attractive and drive them out of the store faster instead of incentivizing sales. (I can't remember the last time I bought a clearance product when it wasn't in one of the $3.50 sales.)

I get a 20% coupon from Prime every month and frequently I end up sitting on it until nearly the end of the month, by which point I've spent the majority of my CG budget elsewhere.