Geocodio allows you to quickly upload an Excel file, CSV, or TSV of addresses and turn them into a map. There is no limit on the number of addresses you can upload (file size limit 1 GB) and the first 2,500 per day are free.
In addition to a map from Geocodio, you'll also receive a downloadable spreadsheet with coordinates that you can upload to any mapping platform. You can also one-click add additional data, such as timezones, ZIP+4, Congressional districts and contact information, school districts, state legislative districts, and Census data.