Can I use my 2 for 1 online and use it against the online price? 2 for 1 vouchers cannot be used in conjunction with any other offers or promotions including the online discounted rate. For information on how to redeem your voucher, please visit here. Related articles How do I redeem a 2 for 1/Promotional Voucher? How can I redeem my National Rail Days Out 2 for 1 Voucher? How do I redeem my Kellogg's voucher to purchase an online ticket? Where can I find information on Merlin Passes? Can I use a 2 for 1 voucher in conjunction with the attraction pass?