Website builders provide free plans and people also make use of them. As a starter, there may be free plans offered, but remember nothing in life comes for free. This is merely a marketing strategy that gets you into working and brings millions of signups.
The problem with website design is that the free builders of website are inadequate typically to offer you a professional website. You will end up signing and invest lot of effort and time in getting a free website build-up. Finally, you will find it to be inadequate and will have to switch finding a new paid service.