"I buy a bag."
Interesting... I learned kaban in hiragana. Any idea why it's in katakana on duolingo? What's the loan word here?
Well, nowadays it's just a Japanese word, so you'll most often see it in hiragana, but once upon a time it was a loan word from the Chinese 夾板 (キャバン).
It changed somewhere in the Meiji period (1868-1912), when it became 鞄 (かばん); a tanned hide used for carrying things.