I'm appreciating all the info.
I'm kind of new to this, and am getting pickier about what I am buying. For right now I just don't have the time to put 5 hours into a bike unless it is going to make 100s. The idea of specializing is a good one, but surely you bend the rules.
What got me into it is that I live where there is no middle class, and their yard sale and thrift store castoffs are in high demand in many places. The full DA Pinarello I got for $50 hooked me. And a yard sale that I made over 1K off of, with a cash outlay of $100. Those 2 payed for my wedding.
Of course, if I spy a high end vintage roadie, I am always assessing if I can make money on it. Seems like the ones that you can part out and make good on have nice saddles. If you look at a bike and you know ebay will produce 60$ for the saddle, and you can buy it for $60, green light.
I am moving to a bigger city and am excited about getting into CL flipping. I was down there a few weeks ago and within 20 minutes of arrival I sold an 80s 4130 schwinn for 150 that I payed $5 for that needed nothing. Later that night I saw the guy ripping around town with some buddies, and he said he had a car. That is mutualism my friends. Kept him out of the car, and on the bike. both benefit.
Just for kicks, and profitability, I checked out the bike shop right next to the college to check price points. You can't get a new skinny tire road bike for under $500. You can hardly get anything under 800$, so high bike shop prices drive the used bike market, not CL listers.
Yes, there is money to be made flipping. Is it that profitable? depends how much supply and demand near you. I know this: It is fun. Going around to all the yard sales early saturday morning, rolling up and looking for drop bars with a delicious cup of coffee in my hand is so fun. peeking in the thrift store daily. The chase of the bike, and the chase of the flip.
and then you have tons of parts for bikes that you can give to friends or donate to youth orgs or ride yourself. Or money to buy what you really want.
Sorry about the long post, but I read all those other long ones ane they were great. This is a great venue for discussion, because none of us are really going to be competing with the others on here for bikes, and if they are, seems like this forum is full of people who aren't that petty, even if they are bartering for a $10 bike with an old lady sometimes.