It's in Euro not in $ - Sorry for that...
Anyway, I don't find the way to dowload it free... Any idea ?
Step 2
you are accessing wordpress.com - that is the wrong website. You want to access wordpress.org.
This is the wordpress.org page for wpForo, which others confirmed is free
wpForo costs nothing, only the addons cost something
You can download wpForo here = https://wordpress.org/plugins/wpforo/
but you need a self hosted wordpress or a WordPress.com account
180€ costs the WordPress.com Pro Account per year, if you want to have it
https://wordpress.com/pricing/
visit my wpForo > Tutrix.de (unofficial german wpForo Support)
with lots of customization & modification, e.g. hover cards, topic/post preview on mouseover, chatbox and much more...
Probably no longer relevant to your question BUT I think useful for you anyway. You can always test on a localhost on your desktop/laptop. That way you can totally test apps like WordPress and free editions of plugins (from e.g. wordpress.org, keep in mind premium/pro editions of plugins will always cost money) for free. This way you won't need to have a webhosting package available just yet, and it is always handy to have in place while developing your site.
Perhaps the easiest solution for you -when this is all new to you- would be localwp.com but there are plenty others out there: MAMP, XAMPP, Laragon (my personal favorite but it needs an massive update of the packages so I've completely updated and patched my installation manually), etc...
