それどこで買うんですか！
お金じゃらじゃらさせなくていいから便利なんですけど！
って思ったら、駅で買えるそうです。
そりゃそうだ(笑)

I thought, "Where can you buy those?! It'd be convenient not to have coins jangling around!" It seems you can buy them at the station. Yeah, that'd make sense. :-)