While looking for a solution to display a map embedded into a web page, I came across several options. My initial idea was to use something like Google Maps or Bing Maps. Both wanted me to sign up for a developer account to get access to their APIs. Additionally, they often impose extreme rate limiting or superimpose intrusive watermarks unless you upgrade to a paid account.
Below is a quick example of what I ended up using it for. You initialize the map with a location ([38, -97] is the geographic center of the US), zoom level (4 seems to fit the entire US), and a tileset (OpenStreetMap). All that is needed to add a marker is a to call the
marker function with decimal GPS coordinates.