Do I have to get my tickets for Free Ticket Tuesday through movietickets.com or can I get a code?

Do I have to purchase tickets through movietickets.com or is there a way to get a code?? AMC movie theaters have $5 tickets on Tuesdays and the movietickets.com website is trying to charge full price for Tuesday showings' tickets. It does not seem fair that we are being charged full price on days where the tickets are not full price for everyone else.