Most museum objects were commodities at one point—a fact that’s easy to forget, since their (often hefty) price tags have since been replaced with reverent wall labels. Of course, these works are no longer for sale. But there is still one place where museum-goers can nourish their appetites to touch and own things of beauty: the gift shop.

Exiting through the gift shop has become an expected (and, for many, unmissable) part of the museum experience. Dr. Sharon Macdonald, a professor of cultural anthropology and the director of the Centre for Anthropological Research on Museums and Heritage in Berlin, even refers to it as “the grand finale, the final exhibit of the show.”

Yes, things like Vincent van Gogh socks and giant stuffed soup cans à la Andy Warhol are hard to ignore. But this blockbuster “final exhibit” is successful for several reasons: Museums anoint objects as culturally and historically significant, encouraging visitors to collect them; the curated selection of merchandise at museum stores differentiates them from other retailers; and proceeds go back to supporting the affiliated museum’s cultural preservation work, making bona fide art patrons out of postcard-buyers.

A 2009 financial survey conducted by Marketing General Incorporated reported that some museum stores net as much as $8.3 million in annual sales (with the average hovering somewhere around $654,000). But the museum retail industry’s beginnings were humble. By and large, the first wave of museum shops dates back to the late 1800s, when visitors could occasionally find a box kept under the information desk with cheap reproductions. In rarer cases, there might even be a small sales counter with some custom items.