Yup. From what I understand, Lightning channels are something like a wallet on the blockchain controlled by two Lightning nodes. There’s a total amount in the channel, and there’s also information about how much each party is entitled to. The fast payment aspect comes from the fact that the distribution of the funds in the channel can be changed by mutual agreement without needing to store this as a separate transaction.

Now, let’s say that you have a channel open with me, and I have a channel open with the person you want to send sats to. You give me sats from our channel, and in turn I give sats in my channel with your payee to your payee. I may also collect some small fee.

But to open a channel in the first place, you have to have some initial deposit, partly to pay for mining fees.

This is all just AFAICT, though.