If you are set on using Primal as your wallet provider, then the only way to have a custom address is to subscribe to Primal Premium.

If you are open to looking into other wallet providers, there are a few options that allow you to set up a custom lightning address.

- Coinos.io allows you to set a custom lightning address for free.

- Minibits has a one-time-fee to customize your lightning address.

- Alby allows free customization of your lightning address, but requires you to connect a separate wallet via Nostr Wallet Connect, or run a self-custody node via Alby Hub.

- Misty Breez allows you to customize your lightning address for free, but it has a minimum receive amount of 100 sats, so it's not ideal for a zapping wallet, since most folks zap smaller amounts than that.

- Zeus lets you set up a custom lightning address for free, but you have to run their node on your phone, with all the liquidity management that comes with it. This will be changing in their next release (currently in beta) that allows users to receive via eCash until they have built up enough to create their first lightning channel.