In Nigeria, if you want to sell a $30 Amazon gift card, there are several steps you can take.

First, you need to find potential buyers. This could be through various online platforms such as social media groups dedicated to gift card transactions, or local classified ads websites. Make sure to clearly state the details of the gift card, including its value of $30 and that it is an Amazon gift card.

Once you have found interested buyers, it's crucial to establish a secure and reliable way of transferring the gift card details. Avoid sharing the card number and PIN in an insecure manner. You might consider using a trusted escrow service if possible to ensure both parties are protected during the transaction.

Finally, after the successful transfer of the gift card details and receipt of payment, follow up with the buyer to ensure they are satisfied with the transaction. Building a good reputation in these transactions can lead to more opportunities in the future.