Hi, cmlumbra. My name is NET Shelly and I will be addressing your question. There are multiple ways on how to add airtime to your NET10. You can buy a new Unlimited Plan or enrol to Auto Refill online through www.net10.com
using a valid credit card or debit card. You can also purchase a NET10 airtime card from the nearest retail store in your area (such as WalMart, Dollar General, Target, & others). Depending on your phone model, you may have the option to add the plan directly from the handset. You can also add plan through the website or the automated response system. Our customer care hotline is open Monday to Sunday from 8:00AM to 10:45PM EST to help you; you can reach us at time most convenient to you at 1-877-836-2368. I believe this answers your concern about adding airtime to NET10 phone. Thank you.