<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by MKE-MR:
...what about the trip which you would NEVER have taken if you had to pay for it?</font>
You completely misunderstand. The value (to you) is the price that you would pay for a particular trip and class of service.
Consider a business-class ticket from Boston to London and back. The price is $8,000.
The value to you is what you would be willing to pay for that ticket. Moreover, and here is a key, the value is different for each individual. For example, if you knew that you could buy an economy-class ticket for $500, you might be willing to pay $1000 for the business class ticket. Someone else might be willing to pay $2000, a business might be willing to pay the full $8000, and a student with limited funds might be willing to pay no more than $525.