How much does each beer cost in a keg?

The math:
15.5 gal per 1/2 keg.
= 62 quarts
= 124 pints
= 103.25 imperial pints (a pint of beer)

Your staple domestic drafts go close to $90 per 1/2 keg, so 90/103.25=0.8717

Each pint of beer in a keg is 87.2 cents. If you think about the price of a pint at your local bar/pub/tavern, you can see why the alcohol industry is a popular one to get into.