Free MQTT Server
We have a public broker were you can do your first steps with MQTT. It is free of charge, already setup and ready to go.
Host: mqtt.iotwithus.com Port: 1883
Topic suggestion: unique-id/* (eg. doorlamp213/stat/POWER where doorlamp213 is unique for every device, try to add some random characters to keep it safe from other users)
You can connect as many devices as you want. You do not need any username / password for now.
I strongly recommend to join this channel on Telegram if you are using this server. Updates on the server will be announced there.