Audio is obviously less data intensive, but can still add up. Spotify, for example, suggests it accounts for 256Kb - this means, in data terms, that you will be downloading around 100MB of data per hour."

You have a broadband 'allowance'...  is that something you get from your mum & dad every week?

typical broadcast digital mono radio is 64 kbps stereo would be 128.

Megabytes per hour = 64 * 1024 * 60 * 60 / 8 / 1024/1024 = 28