It would be very unusual to find a code for PBK. I've worked there the past couple years and the only discounts I know about are as follows.
Employee - which is very good
Moving discount 10% - I think people get this when they already receive catalogs and they change their address after a move. Not really sure how long it takes to receive. I've only processed them. Never actually used myself.
Gift Registry Completion 10% - This does not have to be a baby registry. We do them all the time for birthdays, christmas etc...You just set up a registry, set the completion date at least 24 hours from the time you register and then when you are ready to "complete" your registry let the sales person know you are doing a completion and you will receive 10% off your purchase.
Friends and Family discount 20% - We do these a couple times a year. Your best way to receive them (if you don't have friend or family employee) is to give your email address at the checkout for in store promotions. (not registering online but giving email at checkout in the store) Unfortunately we just had one a couple weeks ago so there won't be another until after the new year.
I hope this helps. If you have any questions just let me know.