Dell Home, via its Member Purchase Program, offers the Dell USB-C 45-watt Power Adapter Plus, model no. Y91PF, for $28.49 with free shipping. That's the lowest total price we could find by $30. It's compatible with select XPS, Venue, Latitude, and Inspiron models and can simultaneously charge a mobile device.
Note: Dell's MPP is available to select groups, including students, government employees, military (active and retired), credit union members, and health care workers.