Online educational marketplaces such as TeachersPayTeachers.com (TPT) have become popular among teachers, but the quality of materials offered is inconsistent. This descriptive study explored quality indicators for site materials. Examining a sample of TPT's 100 best-selling 11th-grade U.S. history activities, we compared overall quality scores (as evaluated by three experts) with user review metrics and store characteristics. Expert ratings were not correlated with average user ratings, the number of user ratings, qualitative user feedback, the resource's popularity rank, or marketing appeal. However, price and the seller's number of followers were positively correlated with expert ratings, albeit weakly. These findings highlight how for-profit educational marketplaces constrain teachers' ability to access and evaluate curricular materials. Ways forward for teachers, teacher educators, and the for-profit platforms are discussed.