On a recent trip to Melbourne, Jen and I wound up purchasing overpriced sashimi from a vendor at the airport. Except we didn't see it as overpriced and were happy with the transaction.
Yet we always bitch about our local (cheaper) sushi joint - because they charge 20 cents for soy sauce. The airport bar does not.
It has nothing to do with the money. Instead it's about the roadblock in the transaction. Additional charges, even minor ones cause friction - what should be a transaction conducted entirely on autopilot is now something with a bump. For god's sake - don't make me think.
As a business we got this one wrong too. Our quotes used to include a large number of optional add-ons, which we thought would help our clients choose the level of involvement that suited them and help manage their costs.
Instead, it just introduced friction.
While most people are generally price conscious, of vastly more importance is for you to simply take their problem away.
By adding in small charges, you force people to think when they really shouldn't have to. In the information economy, attention is currency - even when you're offline.
We should all be aiming for frictionless transactions.
Reduce complexity. Increase value. Create experiences.