In order to minimize the number of fees you incur with Money Earned, consider the total amount of funds you may need on your Spentra Card for the entire day (or next couple of days) and load that amount. Try to avoid doing multiple smaller transactions, as each transaction results in a Money Earned fee.
Also, there is a transaction limit for the number of loads you can put on your Spentra Card. Doing fewer transactions with larger loads results in fewer fees and helps you avoid going over the load limits on your card.