The value of your miles is the equivalent out of pocket cost of comparable travel YOU wish to use them on. Therefore what an airline sells them for at retail although possibly interesting, is really irrelevant.

However if you want to know what airlines sell their mileage for at "wholesale," you can "back into" the number by considering the so called excise taxes some partners [Alamo, Sprint, etc.] will assess you on their accrual. The last time I went through the computation it turned out the partners were representing their actual cost totaled about $0.013/mile.

Therefore wholesale cost appears to be about $0.013/mile, whereas retail cost is about $0.0275 or more/mile.

Does this mean your equivalent miles are worth somewhere in between these two numbers? No. Again, the value is what it would otherwise cost YOU for comparable travel and that cost varies from person to person.

Thus if you can purchase a coast to coast advance purchase restricted round trip economy seat that itself accrues close to 6K of frequent flyer miles for $250 or less; you assume the 6K of frequent flyer miles are worth their wholesale cost [$78]; and to secure the same ticket using frequent flyer mileage would cost you 25K miles plus $20 in taxes; your 25K of frequent flyer miles are really worth about $150 or less, or roughly $0.006/mile.

On the other hand if you use 80K of your frequent flyer miles on a low season European round trip business class ticket that costs $7K, your miles are being valued at nearly $0.09/mile.

Would you rather use your miles for travel worth less than half a cent/mile or travel worth 18 times that amount?

If you don't have the luxury of waiting to use your frequent flyer miles for travel worth $0.09/mile then what I use for a "rule of thumb" is $0.0125/mile. Simply stated if my travel costs less than comparable frequent flyer mileage redeemed at $0.0125/mile I generally purchase it. If it costs more I then CONSIDER [on a case-by-case basis] whether or not to use my mileage instead. Once my cost of travel hits about $0.015/mile and given a choice, I almost always will use mileage instead of cash.

Hope this helps you in answering your inquiry!