How many customised templates can I create?

I’m creating a website with the free template named Pieria.

My goal is to have different sidebars for every article I post, as long as they will contain always different informations about the author of the post and an image connected to what the post says.

So every time I create a new post, I create a new template, as long as it’s not possible to change the contents of the sidebar every time.

My question is: with the free version how many customised templates can I create? Is there a limit?

I know I could simply keep the same sidebar for every post but this is not the aim of what I’m creating.

If what I said is not clear, let me know and I will add a screenshot.

Thanks a lot in advance for your answers.