Is a keg cheaper than cans? Whether a keg is cheaper than cans depends on what brand of beer you purchase. The keg itself may be less expensive than buying individual cans–but you have to factor in the cost for cups.
“If you plan on about one drink per hour per guest for a 150-person reception that lasts 5 hours, you'd need around 750 drinks." So that would mean, if you're only serving beer, you could use up to six kegs or nearly 30 24-packs of bottles or cans.