Do I need a Nano SIM to turn on my iPhone or can I just activate it to turn it on?

I got a new iPhone and it said it needed a SIM card, I took out a SIM card out of my tablet and it didn't work (Because it was a Micro card) and I was wondering if I can just activate it through phone call(I have straight talk) or do I really need a Nano SIM card?

Your phone needs a sim card to function as a cell phone. You can buy the right sim card at walmart.

SIM card is must for activation and you've StraightTalk which is GSM. It's not a problem though, you can just go to any phone store or Walmart and have your SIM trimmed to nano-SIM. Then you can activate the phone.

SIM cutter will look like this: http://www.amazon.com/...B003UEWF8I

But no need to buy, any phone store will do it for free.