Do you do Free or Paid access to your SaaS at launch?

So, I keep seeing conflicting information on YT about offering free or paid at the start of a SaaS -

'You should offer free access to get users' or 'You should make your SaaS paid at the start to weed out tire kickers'.

As there are many people here who have a successful Saas, I was wondering what your take is on this.

I thinking about just adding a button on the home page, right at the top that will let users try the app with no sign-in or sign-ups, if they want to upgrade, they can do so at anytime, from usage stand point the app runs in their browser so no real strain on my server.

What do you think about this onboarding process?

Any help would be great. Thanks