we have a prepaid phone for our kids..thru ATT..the minutes are good for 45 days,,then you lose them unless you ad more minutes before the 45 days are up..if you ad minutes the other minutes carry over,,,,,you can ad as little as $10 at a time..so 10 for 45 days isn't bad, I don't have to run to a store to ad minutes I just call the ATT number and ad minutes using my debit card....