Translation:How much is the bag?
"how much does the bag cost" isn't the same as "how much is the bag?" Really Duo? Really?
It may be 'カバンの値段(ねだん/cost,price)はいくらですか？' Though I'm not sure because I'm not Duo. Maybe.
I've seen 鞄 written as かばん more often than カバン. I'm just really glad that they didn't use kanji for this, since it is almost never used.
I know that この isn't there but is "How much is this bag?" Really a wrong answer? :/
Oh, I didn't realise it was a loan word- I'm guessing that's why it's in katakana. What language does the term come from though?
In American English it is much more common to day "How much (money) for the bag?" than, "how much is (the cost of) the bag?"