Instructions:Just got an email from Photobox saying:
MY50PRINTS - 50 Complimentary Prints for you
This offer entitles you to 50 complimentary Standard Prints (6"x4", 6"x4.5" and 5"x3.75"). Offer is exclusively available to PhotoBox newsletter recipients. Offer can only be used once per account and excludes postage and packaging. Offer ends 11:59pm Tuesday 29th March 2011.
Use the code : MY50PRINTS Unfortunately the postage is not free.