OK, here is my standard rant on why that's not a good idea.
Those coupons are coded with your info. If you use your shopper's club card, if they come from the company, whatever, your personal info (like the fact that you bought breastfeeding related stuff and are breastfeeding) are encoded into them. When the coupons are used (even by someone else) the only message the formula company gets is "Hey look! We got another breastfeeding mama to buy some formula- this marketing tactic really works."
This is not good for anyone. It gives formula company's the OK to market aggressively to breastfeeding mamas. It drives up the cost of formula for all formula feeding mamas, including the ones with a genuine need for formula.
Please, please, pretty please, just throw them away.