I don't know your market, but the bike seems like a poor choice for an upgrade-then-flip.
Paying only $20 for it was a good deal, if you needed a bike for yourself, as it might be "good reliable transportation." But I don't see it ever being worth over $100, for the reasons T-Mar listed.
Your market may vary.
Last edited by NJgreyhead; 11-20-17 at 08:33 AM.