With Koodo there are no contracts (WOO!) What they have are tabs, its like an interest free loan for the phone. You can get either 360$ or 504$ off of the price of the iPhone and put it on that tab. If you put the 504$ on the tab, then you will select a tab plus plan, which honestly is not worth the money for what you get. If you put 360$ towards the tab, you can select any of the current plan offerings from Koodo. To pay off the tabs, Koodo devides the amount of the tab by 24 and the answer becomes your monthly tab contribution.
You can sort of guess if you are eligable, Jessica. For starters, you need to be of legal age in your province (18 or 19). Your credit has to be in fairly decent (but not top notch) condition. If you have never been declined service or credit, you are probably good to go.
But as Mathieu said, the only sure way to find out is go up to a kiosk and ask.