Here is a little bit of information off of Wikipedia that will explain to you the sacred use of this object and why some Native american cultures may take offense to someone selling or creating these kind of objects.
While dreamcatchers originated in the Ojibwa Nation, during the Pan-Indian Movement of the 1960s and 1970s they were adopted by Native Americans of a number of different nations. Some consider the dream catcher a symbol of unity among the various Indian Nations, and a general symbol of identification with Native American or First Nations cultures. However, other Native Americans have come to see dream catchers as over-commercialized. Non-Indians have also used the dreamcatcher for their own purposes.
In the course of becoming popular outside of the Ojibwa Nation, and then outside of the pan-Indian communities, "dreamcatchers" are now made, exhibited, and sold by some New age groups and individuals. According to Philip Jenkins, this is considered by most traditional Native peoples and their supporters to be an undesirable form of cultural appropriation. Even though some Native Americans appreciate their culture spreading and enjoy selling and dispersing their homemade dream catcher 
My personal opinion: I like the meaning of a dream catcher I create mine as a work of art and use it for my own purposes and beliefs. In no way am I trying to misrepresent or disrespect native american cultures. When you create something it is yours... good ideas will always be copied and transformed.
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