I'll have to ask my wife - but banyak2 (they sometimes use the power sign for those words that are "doubled" (makes it plural) - sounds like informal slang. Many times when you say terima kasih, they will reply "kembali" (back to you). Once, when talking with the wife of the Consular General of Indonesia in Toronto, she said "Apa kabar" (literally "what news?"). I answered "Bagus, dan kamu?" - they never say " good, and you?". She had a bit of a laugh about it.