My apology for reposting another thread. I'm very confused

My apology for reposting another thread. I'm very confused and frustrated trying to figure this out and I will try to organize my thoughts clearly so I understand.

What I am trying to do:
1. I am creating a website builder service like squarespace.
2. I would like to offer a "free" trial for people to try it before they buy it (14 days) without entering a credit card.
3. When the trial is over it makes them upgrade to a "paid" level.

Questions:
1. What is the difference between "free trial" and "free level"?

2. How can someone try the site that they register without entering a credit card?

3. What happens when a site cancels or a trial membership never upgrades? Does it auto-delete their site so my MU isn't bloated with fake accounts?

I hope this makes sense. I can't seem to get a clear explanation on the forums.