Requirement as Beginner
Mas is your basic requirement to start development. you need to buy new mac mini, imac or mac laptop for development. you also require iPhone for testing purpose. you can buy apple product from official web site http://www.apple.com and you can also buy product from apple reseller.
Apple Developer Account
you need to create apple developer account though official website http://developer.apple.com
developer has to pay subscription USD $99/per year. you can publish many application to apple store.
Xcode
To start developing iPhone and iPad apps, Xcode need to download and install on your mac. Xcode is an integrated development environment (IDE) provided by Apple company. Xcode provides everything you need to start your apple app development. It already bundles the latest version of iOS SDK (Software Development Kit), its a built-in source code editor, graphic user interface (UI) editor, debugging tools and many more. Most importantly, Xcode comes with an iPhone (or iPad) simulator so you can test your app even without the physical devices on iPhone simulator. you can download xcode from app store free of cost.