Getting a free blog account is fairly easy, especially if you have a Google account. Google accounts are free so the free Google blog account is in fact free. If you do an online search for free blog accounts you will find other free offers. Some of them say "set up a blog account for free". This means that there is no charge to set it up, only to operate it. Free blog accounts should not charge monthly fees.
Once you have found a free site you will have options about the appearance of your site. You will be offered a selection of templates, some of which may not be free. Some of the free sites may want you to choose advertisements to run on your site. The advertisers pay for being on your site and may even pay you for business generated by your site. As long as the advertisements are not offensive to you this arrangement should be no problem. Someone has to pay for the expense of operating your site.
Try to know in advance why you want a blog. The different free blog account sites each have their own orientation. If you are trying to set up a business there are a number of sites oriented to business purposes. The Google site is more for personal use but does allow legal business. Have fun with your blog.