Can I try Snaprime for free?

Yes, on the Free plan. It lets you prepare 1 campaign and 5 ads along with a page; you just can't launch it to Meta. To launch, simply move to the Start plan or higher, and your prepared campaign stays.

Some offers, such as from a webinar, include a trial with a payment card. You'll see the trial terms and end date on the sign-up screen and in the Your plan ("Váš plán") section. Go by those, not by older emails or videos.

The trial covers the app. You always pay Meta for ads yourself, and if ads ran, Meta will still want payment even after you cancel your subscription.