Mapbox is awesome, but there are alternatives for hobby projects, such as https://www.maptiler.com/. I wrote about some more here: https://barnabas.me/articles/webmaps.html#map-tile-servers-a...

If your project is confined to a limited geographic area and you don’t need super high zoom levels, you could even host the static tiles yourself without too much trouble and disk space. It can be very cost effective.