Does ipad mini has a sim card slot?

If the mini is a Wifi + cellular model it has a SIM card slot (you may have to get the card from your cellular service provider). However, the cellular service on an iPad is separate $ from your phone cellular plan.

 Cheers, Tom 😉

Since you have an iPhone, there's another option to consider.

Use Bluetooth to tether your iPhone, iPod touch, or iPad

http://www.macworld.com/article/1159258/bluetooth_tethering.html

How to Connect an iPad to an iPhone Via Bluetooth Tethering

http://techtips.salon.com/connect-ipad-iphone-via-bluetooth-tethering-25472.html

How to Pair Bluetooth Device to iPad

http://www.ehow.com/how_6194904_pair-bluetooth-device-ipad.html

 Cheers, Tom 😉

look here for the specs:

http://www.apple.com/ipad-mini/specs/

select the iPad mini that will work with your carrier.

Check with your carrier & see if they allow you to switch devices.

Robert