You should check with your local Howard County Extension office.
According to this page, the Master Gardener program offers free rain barrels, distributing occasionally from the landfill: https://extension.umd.edu/mg/locations/bay-wise-landscape-management
Their contact information is here: https://extension.umd.edu/mg/locations/howard-county-master-gardeners
Thank you! We will be visiting the Alpha Ridge Landfill on 7/20 to get our rain barrel!