There has been lots of (digital) ink spilled on the value of frequent flier miles.
Two of the best analyses:
Frequent Miler's Fair Trading Prices (
http://boardingarea.com/blogs/frequentmiler/fair-trading-prices/
MileValue's Leaderboard
http://milevalue.com/mile-value-leaderboard/
And my own opinion, similar to Ken's: don't pay for miles! Usually the value you get from redeeming them is going to be less than or equal to the price you'd pay for them.
Nearly as bad as bad as paying for miles is earning them a mile per dollar spent with an airline credit card!
Assuming you have good credit, it is far, far too easy to get a lot of miles as signup bonuses for credit cards or for shopping via online shopping portals.
And there are a LOT of different credit cards available.
I'm a bit of an addict, admittedly, but in the past two years, I've booked RT tickets for my family of five to Costa Rica, Peru, and Aruba with frequent flyer miles. Also my husband and I are flying in Singapore Airlines First Class to Russia. And we have many miles still available.
So please don't buy miles
But tell me where you want to go with miles, and i'll help you figure out the best way to get them. PM me, or check my website
Anita