Give the best one away
The instinct, when you make something good, is to charge for it, and to charge more for the better stuff. It feels like basic math.
For the front door, that math is wrong.
The free thing does the selling
My most-downloaded products are free. Thousands of people have one of them. A fraction of those people then buy something, because the free thing already proved I'm worth trusting. The giveaway isn't charity. It's the most effective salesperson I have, and it works while I sleep.
A locked door asks strangers to trust you before they've seen anything. An open one lets the work make the argument for you.
The free product's job is to earn the right to sell the next one.
How to pick what to give
Give away something genuinely useful, not a teaser built to frustrate. The goal is for someone to finish it and think, if the free one was this good, what's the paid one like. Cheap bait earns cheap trust. Real value earns a customer.
Put your best foot through the door first.