You set the price. Your share is 50% of it, before your own taxes. The price sits on the channel, under Channels → your channel.
Picking a number
There is no right answer, but two things are worth knowing. A very low price is eaten by payment fees before it reaches either of us, so the panel enforces a minimum. And a subscription is a recurring decision: people compare it to what you post in a month, not to what you posted today.
Changing the price later
You can change it whenever you like. People who already subscribe keep the price they signed up at until they cancel; the new price applies to new subscribers. If you announce a change in your public channel first, your existing subscribers hear it from you rather than noticing it later.
Longer periods
Where longer periods are offered, the panel shows what a subscriber saves against paying monthly. A longer period means the money arrives sooner and cancels less often — it also means you have promised more posts.
A channel without a price
It stays connected, it stays yours, and it earns nothing: the bot has no product to offer. The panel marks it as Base price missing.
What the subscriber sees
The price, the period, and what they get. Payment goes through Netfield, and access follows the payment: the moment it clears, the bot adds them. There is no manual step in between and nothing for you to approve.