Can I use a phone card from my cell phone internationally?

Can you re use the same prepaid cell phone card more than once?

• I'm through walmart's prepaid service called Straight Talk. I have been with them for a few months now, and I have noticed that if you buy a 30 dollar calling card for 1000 texts and 30 MB of data, they don't keep track of the texts and internet usage, and it's like you have unlimited everything. They even have a $45 unlimited calling card, but if you buy the $30 card I just talked about, it's pretty much the same thing and never counts down your text messages. I was wondering how a prepaid company can keep track of every single calling card that someone buys from Walmart? I was going to test out, and use my old calling card from last month to see if my service can refilled, and when it says wrong number, or doesn't work, I'll just be like I grabbed the wrong card. I purchased a new calling card for when my service ends, this would just be to test out to see if my method works. Any info will be helpful.

• Answer:

  Never