check out www.hotcouponworld.com they may have your stores available listed along with thier coupon policies for each individual store
in my experiance, if an item is buy one get one free (also know as bogo sales) you the customer is buying one, the store is choosing to give you the 2nd one, there fore they should be able to take BOTH coupons ---you can also wait to scan your "savings club card" at the end of your transaction before you pay, they get reimbursed for EVERY coupon submitted correctly PLUS 8 cents each.
there are a few different ways stores will ring up bogo items (for these scenarios we are just going to assume the item is chicken nuggets and the regular not on sale price is 6.00)
first way:
chicken nuggets 6.00
chicken nuggets 0.00
2nd way
chicken nuggets 3.00
chicken nuggets 3.00
and yes, even in the first way where it can show as the 2nd one being free, you can still use a coupon on it, because the store can still be reimbursed
clear as mud?