The curriculum marketplace Teachers Pay Teachers (TPT) claims that 85% of educators in the United States use the site. Despite substantial evidence that TPT offers low quality materials, little research has explored the impact of TPT on curriculum-making. We analyze 76 TPT seller sites from assignments submitted by teacher candidates in an elementary social studies methods course to understand how teacher education candidates encounter and make sense of TPT. We observe that TPT produces siloed 'one-stop shops' that attempt to capture users' attention, discouraging the kind of legitimate peripheral participation and resource sharing described by the proponents of 'teacherpreneurship.' We offer an alternative model of curricular supplementation that builds on the affordances of platform technologies.