The software from WordPress.org
The answer is that for the actual WordPress software, your hosting company should not be charging you. However, they might have some other blogging software that they are offering to install for you that might be charged for. Do not get confused between free WordPress software and any other software on offer that you might be being offered.
As for the rest of the list, then you might be eligible to be charged for it.
Hosting the new blog
With the hosting of the website and the database, then this is what hosting companies are selling and they are fully entitled to charge for it. How much? Well, that depends on the hosting company entirely! Some offer more additional extras than others and these are what you are paying for. They should definitely be offering services such as backups to protect your site.
Installing your new WordPress website
Installing the free software, and even updating it in the future, can take time. And it is fair that a business who is investing the time of their staff in providing you with a service should expect you to pay for their time that is used. So the installation could be charged for, although usually with the bigger hosts the installation is totally automated from a single click of the mouse.
Including some useful plugins
Lastly, we can look at the add ons. Here a lot depends on who has written them. For a few WordPress plugins you need to pay for licenses, although for the majority this is not the case. So if your hosts are providing some of their own plugins it is up to them if they are charging for them or not. However, when they are installing third party plugins for you, it is almost certain that any charges would be paid to the author, not your host.