Many couples think that it is okay to have cash bars, when in reality, it isn't!
How would you feel if you were invited to someone's home for dinner and then they asked you to pay for it?
You would be very upset and offended. Now you know how your guests feel.
But I can't afford to buy drinks for everyone!
Then only serve what you can afford. Beer and soda is enough. A champagne toast only is enough.
Your wedding is an elegant affair, a beautiful event to celebrate the beginning of your lives together, not a drink fest for your friends and family.