The Third Class Relics on this web site are the same Third Class Relics you would purchase if you traveled to the shrine of the saint and purchased Third Class Relics there.
First Class Relics - Actual part of a saint (a bone, a hair, a limb, etc.) Second Class Relics - An item that the saint wore (a sock, a shirt, a glove, etc.) Third Class Relics - The Third Class Relics on this site fall into 2 categories. The first category is a piece of cloth touched to a (first or second class) relic of the saint. Second category: In cases where there is no known existing relic of a saint, the cloth has been touched to the shrine of the saint.
It is prohibited by the Catholic Church to sell First and Second Class Relics. When the Church prohibits the selling of "Sacred Relics" it is referring to First and Second Class Relics. It is not referring to Third Class Relics.