marginal cost
incremental cost
differential cost

It does not effect the marginal cost, but still needs to be paid for.

But the marginal cost for the 1,000,000th person will by tiny.

Figure 16-2 also shows the marginal cost of producing the public good.

Products and services with a marginal cost of more than zero, for example.

It all comes at you in marginal costs, £8 to £9 a mile.

The marginal cost of this is pretty close to zero, so it's easy for them to share.

This additional information must, moreover, be made available at marginal cost.

To find countless items of low marginal cost and just include them.

Market power is the ability to increase the product's price above marginal cost without losing all customers.

A more telling economic assessment might be the marginal cost of electricity.