The gods sell all things at a fair price.
Something you don't want is dear at any price.
A thing is worth what it can do for you, not what you choose to pay for it.
Why so large a cost, having so short a lease, does thou upon your fading mansion spend?
The cost of a thing is the amount of what I will call life which is required to be exchanged for it, immediately or in the long run.
What you get free costs too much.
The gods sell to us all the goods which they give us.
Expenditures rise to meet income.