“We estimated that on an average American cell data plan, each megabyte downloaded over a cell network costs about a penny. Visiting the home page of Boston.com every day for a month would cost the equivalent of about $9.50 in data usage just for the ads.”
Source: The Cost of Mobile Ads on 50 News Websites – The New York Times
I’d venture to say that local TV and news sites have even more ads than boston.com and “cost” you more in data downloads each month. There’s a reason local news stations are eager to promote their content on Facebook and why most engagement and comments happen there rather than on their own sites.
If your business, group, or church site is loaded with plugins, images, and unnecessary animations (especially Flash), you’re already likely being penalized by Google in organic searches as your site is not as mobile friendly as it should be.
Keep that in mind when you open your own site on your mobile device.