Contact Enhanced has maps integration with Google Maps API (requires billing information) and with Leaflet to show a map based on the contact address. If you have a Contact Enhanced PRO subscription you can also use the Ideal Store Locator plugin, which has integration with Google Maps API only.
Leaflet is the leading open-source JavaScript library for mobile-friendly interactive maps. Leaflet is provider-agnostic, meaning that it doesn’t enforce a particular choice of providers for tiles. Leaflet doesn’t even contain a single provider-specific line of code, so you’re free to use other providers if you need to.
Some Tile providers are free to use. This doesn't mean no limits apply, you should always check each of the provider's Terms and Conditions before using these layers for anything serious. There are some paid providers with a free quota. For example Mapbox.com provides 50,000 map views for free. Most free providers, if not all, get the map data from https://openstreetmap.org. OpenStreetMap is a free, editable map of the whole world that is being built by volunteers largely from scratch and released with an open-content license.