Pints of beer do NOT cost bars anywhere close to three dollars and fifty cents.
one hundred and sixty beers per keg roughly, and take away like twenty for spillovers or freebies, youre looking at them paying like thirty or forty dollars per keg, since they buy in quantity...
So on the beers that they sell, not counting the freebies per keg, they're paying a quarter a beer.
I'm pretty sure they can cover a CC charge.