영어 대표 튜토리얼
https://parse.com/docs/ios_guide#iap/iOS
한국 튜토리얼
http://m.cafe.naver.com/app/ArticleRead.nhn?wCmt=true&articleid=200626&query=%D7%BA%88%EA%B7%B8%EB%A6%AC%EC%8A%A4&boardtype=L&menuid=177&menuType=B&clubid=16914752&commentCount=33&commentNew=false