Well, so far it's been a matter of convenience... for example, I'll just go with what I've got in the garage right now... 3 department store mountain bikes, one 80's Huffy DS road bike, and one AMF Roadmaster Scorcher that I picked up last night. When I went to pick up the Scorcher, the guy had like 2 more broken bikes and two DSB wheelsets that he gave me because he was just going to take them to the dump had I not arrived...
So far total cost for 7 bikes... $15. If between those seven bikes there's enough good parts to make one of them work (there are, minus the cables), I can without any parts cost (other than the aforementioned cables) double my money if I can even sell it for $35... and most of mine have sold for $40-$50. My margin comes from the fact that people give me stuff... because they want it gone.
I want to upgrade to 70's & 80's road bikes, but the reasons I haven't so far are as follows:
1: Anything that's not a DSB disappears on CL in less than 20 minutes here. If you're not sitting in the middle of town with cash in hand and a laptop to call as soon as it shows up, you're not getting that bike. There are a billion other college students around collecting low end LBS bikes to make into fixies and flip. They don't have full time jobs, and I do. So by 5:30 pm, it will be gone.
2: There are 3 markets for bikes in this town: roadies, hipsters, and moms/dads looking to ride with their kids. The roadies are going to buy from the LBS. Period. Their bikes usually never end up on CL, but even when they do, they're both too expensive for me to buy, and I'd never be able to get rid of it because anyone who wants to become a roadie will go to the LBS. Hipsters each have a stockpile of at least 10 old road frames which they are going to turn into fixies, and those compose maybe 5% of CL traffic. The hipsters are also the reason that anything good disappears in 20 minutes or less... The remaining 94% or so of buyers are broke moms and dads looking to ride with their kids, and rather than paying $75 plus tax (lowest priced adult Walmart bike) they want to pay $40 for the same bike off of CL. Whether that's a good idea safety-wise or not is a valid question, but they don't know anything about bikes, and although every one of them has heard the shpiel before about how they should buy from an LBS, not a one of them understands why they should pay 8x as much for a bike they're only going to ride once every couple months with the kids. They are the ones blowing up my phone wanting me to find a bike for them... so apparently there's some reason they don't want to go to walmart to get a bike, and they're as yet an untapped market. AFAIK there's me and one other guy in town selling these things in any condition other than "We left it out in the rain for 3 years and we want it gone."
Anyway, so has anybody else run into the same problems of stuff disappearing too quickly? If so, how did you get around them?