A somber flag ceremony marked the opening of the National September 11 Memorial Museum in New York City on Wednesday.br br The museum displays a wide range of artifacts from the 911 attacks, which killed nearly 3,000 people in 2001.br br But it's the gift shop of the museum that is causing controversy.br br Some, like Helen Hatfield, think it's unfair to sell memorabilia at the site of such a great tragedy.br br (SOUNDBITE) (English) HELEN HATFIELD, 911 MEMORIAL VISITOR, ALSO FROM TEXAS, SAYING:br br "I don't think it's a good idea for people to make money off the memorial. It's a tribute to the people who were killed here. And I just think that would cheapen the value of the memorial as a whole. And we want to think about the people, not about souvenirs or making money or anything like that."br br Others take issue with the price tag of some items, like a wool scarf for 95 dollars or a plush toy dog for 19.95.