not trying to advertise himtel, but their $5 card always gives me 13mins and has always worked. I stopped buying those $2 cards even though they promise 23mins. Once in a while i get the 23mins but most of the time it's either the stupid NTC message or too much static to make a conversation. The last few times i could hear my parents talk but they couldn't hear me. So, even though it's expensive i have started using the $5 card....it works most of the time on the first try and is crystal clear.