Is there a free IPTV channel?

Yes, definitely. There are free IPTV boxes out there that you need not pay a dime for. For example, Kodi, which is a media player is continuously being developed by the open-source community is an application anyone can use.

Do you have to pay for IPTV?

Yes, of course. Who gives IPTV for free over the internet or the world at large? Impossible for one for free. You will have you subscribe. Therefore it is never a free service

Is IPTV legal?

Yes, it is 100% legal. However, streaming it, is another question and where you reside will determine if you can stream IPTV or not. It is that straight forward and simple.