When I was brainstorming startup ideas once I mentally kicked around "AirBNB for self-storage," but liability issues and what I saw as a trend towards minimalism among those who would have been a target demographic as reasons to discard it.
We'll see how that plays out as they age, which tends to include things like getting married, having kids, buying a house, and that kind of thing. For instance, our garage now contains 2 strollers, 2 kiddy scooters, 3 kiddy biycles of varying sizes, and one sort of push-tricycle thing. I didn't have all that crap when I was younger, either!
I heartily agree with the advice elsewhere to look at "boring" and "unsexy" stuff. It also helps if it's "far from the tree" in the sense of not picking something that's immediately related to the world you know as a programmer.
It kills me how much money is dropped on kids stuff that is not used for a significant period of time.
craigslist is fine if you have time to sift through things. I'm looking for a site that does it better with filtering to cut out the cruft. Maybe FOBO but a specific subset?
Also, no kids yet. =)
-pricing is rational and stable. In such markets, people just know 'what stuff goes for'. -where the savings of buying used is >$100, then the transactional costs of an email, a couple texts, a trip to the ATM, and a short drive are worth it to a lot of people. -no taxes, fees, waiting for your money, account signup, email subscriptions, app downloads, etc. etc.
When items like those are no longer needed the trend among my peers is to donate (to friends with younger kids) or liquidate (on Craigslist).