Might as well ask how to equalise the cost of letting someone live instead of taking their possessions

The price should be whatever it costs you when including all cost factors¹. A competitive market is an attempt at a system (no central control) to approach that lower bound value. It's really hard to incorporate the million dependencies in a true cost price, so people are instead free to set a price and consumers are free to choose a vendor that's cheaper, and so there's competition. Markets are said to not be working well (lack of competition, usually) if the price of a good or service does not remotely approach the cost price

Bribes are usually to people in power because otherwise you'd just go with the non-corrupt option. That's not a functioning market. I wouldn't say that this type of monopoly is an attempt at determining the fair price for transporting an item of a given mass and dimensions

¹ this really includes everything: to be able to walk across the street and deliver packages, you needed to eat the night before; you needed to learn to read; you need to put money to the side for when you're of age; etc.