[Hint. It doesn’t exist yet.]
Technology makes things cheaper. Cheaper to operate. Cheaper to build, maintain and streamline. So why then do we have a wide variety of businesses from government agencies to movie theaters that charge their customer more to use their online system?
Charging your customers extra to use your online system is completely backwards. Yes, it saves them time and hassle, but it saves you some too. Pass on the greatness of not having to deal with processing one more transaction by hand and give your customers the same price they get at the door, or better yet, cheaper.
[One way this could work would be to go up on all your prices $1 at the door (or office, etc.). This would entice people to purchase ahead of time saving you both time and hassle. There’s more ways, I just offer this one.]