There is no way to create Product Level Coupon Codes for Bundled Offers.
While BUNDLED OFFER is a great feature to create Combo Product Packs with more economical price, there is no way to create a COUPON CODE that can be applied to BUNDLED OFFERS. For all practical purpose, BUNDLE OFFERS are essentially GROUP PRODUCTS with its own unique SKU CODE. Hence, the Product Level feature should also be applicable to the BUNDLE OFFERS. I will like to see this feature to be considered and implemented for BUNDLE OFFERS.