Since I've been bankrupt, I've not been traveling as much by air (or at all-once in two and a half years). I used to for a variety of reasons, participate in airline travel several times a year.
Because I've not flown on USAir in awhile, I got my frequent flier miles yanked at the end of 2007. I had the options of losing the miles, taking a flight, or paying a yearly fee for the privilege of keeping my 28,000 miles.
What I have discovered is the two other airlines I have miles with now have a way for me to earn miles. I log into my frequent flier account and then I connect to a specific retailer-(Ebay, Half. com, Lands end, Circuit City). Presto! Frequent flier miles posted to my account. I bought a couple new skirts and a couple books and DVD's over the summer and now have "re-activated" my mileage accounts. The only down part to all of this was had I paid attention to the marketing e-mails about this promotion, I could have gotten a one time mileage credit of 3,000 for my phone upgrade that I did late last winter. It's not a retroactive credit regretfully.
I don't do that much shopping, but the odd purchase or two each month has kept my accounts active, and I occasionally earn multiple miles for each dollar spent.
Even those of us in budget mode should check this out. Think about it, frequent flier miles for your E-bay purchases!