Here’s what you do.

1. Have a transaction that you already would like to make. For instance buying something, receiving a paycheck, etc.

2. Instead of just making that transaction, open a lighting channel with the person you’d like to make it with (or with an LSP they are connected to, or really any routing node which offers good uptime and fees)

3. Make the on-chain transaction, but send them the sats in the newly opened channel. You’ll now be able to receive the exact amount you sent back into your lighting channel, without having to pay on chain fees again.

Ideally, you’d do this with a big transaction, so that you’d have enough inbound liquidity that you’d never have to go back on chain for anything small. Big transactions are meant to be settled on chain, and the associated fees don’t matter as much as a percentage of a big transaction.

If I were running an LSP and were more tech savvy, I’d try to find a way to open channels which are balanced from the beginning, and then charge slightly higher routing fees to earn sats for the investment of capital. But if you understand how lighting works, you can use it in a very efficient manner already by taking simple steps to make sure your initial channel is big.