I freely admit to not being a flipper. A successful flipper would find a valuable bike for less than $50 and not use more than a good wash, a drop or two of lube and some air for the tires. Bikes often find me, not the other way around. This past fall a neighbour came to me with a proposition. I sell his bike and he takes half and I get to keep the rest. Sounded like an easy deal, the bike was a fairly well looked after 1985 Rossi (shop brand for Scattolon Cycle) 12 speed in a 23" frame (my size!) and 27" alloy wheels. The frame was made in Japan for the Guvin /Miele company.
I couldn't do it! I realized I have never sold a bike I did not service, replace tires brakes etc. and did not want to start. I told him I would would consider it but ended up offering him $60 and he settled for that. The bike is now rebuilt and looks great but I have another $120 in it. If I'm lucky I will get my money back, if not I ride it.
Facebook marketplace prompted me to buy a 1995 Norco Katmandu MTB for $50 late last summer. It looked pretty decent but ended up costing $160 plus parts bin bits. Again, my size and now converted to a drop bar gravel bike. Maybe I wont sell it.
Also on our side is what I call "bike dollar averaging". Sometimes a bike is free (a DL1 and a Sun eg.) and sells very well and and makes money. That money can be used to keep the wheels going around. Last spring a friend had to clean up a relatives property and brought 2 PU trucks full of tarp stored bikes he had collected. Parts and five re-buildables helped the bank. Overall I have netted about $600 / year over the last 10 years. Not a living, but a tremendous amount of fun and my own "fleet of bikes".
Appearance and the sellers reputation is important to most buyers especially local ones. Many of my bikes have been purchased in parcels by Toronto buyers at bike shows so they must be valuable there.
The Rossi before picture.
The Rossi after picture.
Norco Katmandu as purchased (after a good wash)
The Norco as a drop bar gravel bike. It rides great!