Each page load for this article is 485 KB data, but some of the other pages are more like 1.5 MB
This blog has seen 14,000 views today, but some of the other pages are ~38-40k views
So if you assume ~990KB average page size, 30k views, and he were to post once a day, then that is $78/mo in bandwidth costs assuming 9c/GB. Maybe people tend to click around to the homepage / old articles, or refresh the page a few times?