If i buy an unlocked iphone off of kijiji and then put my koodo phones sim card into it, will it work?

Yes, you can definitely use unlocked iPhone 4 with Koodo. The only complication is 3G, I'm not sure if you will get 3G on your iPhone but you can use EDGE and WiFi though. The phone has to be unlocked, the SIM has to be cut into microSIM and then you can pop it in the iPhone 4. If you need unlocked iPhone 4 cheaper, you can mail me to manchurianp@yahoo.com