The data itself is free. Current map tiles on tile.osm.org is hosted on donated hardware, and run by volunteer sysadmins. That's not free. they reserve the righ

The data itself is free. Current map tiles on tile.osm.org is hosted on donated hardware, and run by volunteer sysadmins. That's not free. they reserve the right to block you for any reason at zero notice. Don't run your business or app relying on that. :) There are plenty of companies who take OSM data and make map tiles. Those charge money or give it away for free.