An unknown seller is selling his bike frame for 500 euros, private sale. You, the buyer, know it’s worth at the very least 1200+ euros.
A) Do you pay him the 500, take the frame, and leave.
B) Educate the seller that his frame is worth more than the 500 asking price, pay him 800 euros (or true market price), take the frame, and leave.
C) Do nothing.
D) None of the above.
Ok, I'll bite.
Disclaimer: I am, by trade, a rampant capitalist (but I've been called worse)
Honestly, I would buy it. Why not? And you know what, I'd probably see if they'd take 450 for it.
If it was a frame a I wanted, I'd congratulate myself on my good fortune, probably post it on here to say "at last I got a Nimbus 2000, at a great price, too" and build it or hang it on a wall and look at it.
If it was a frame I cared nothing about, I might sell it on and buy bits I wanted with the proceeds, or swap it. Or build it. Or hang it on a wall and look at it.
Most likely, I'd keep it and see if I grew to like it. It happens. I got my Pace RC200 because I put a low snipe on an ebay auction 3 days before the end. I do this a fair amount - I put in the maximum I am willing to pay, and leave it. If it's something I want, that maximum is high compared to my expectation of the finishing price, and vice-versa. Doing this means I never pay more than I want to, but sometimes I pay less. If I don't win an auction for something I want, I didn't want it enough.
To my genuine surprise, I won that RC200. I was pleased as punch - I'd never owned a Pace before, didn't "want" one, but the opportunity to get my hands on one to see what all the fuss was about was welcomed. If I didn't like it, I was happy I could sell it on here. Worst case, I'd lose a few quid. Best case I'd make a few.
As it turned out, I was wrong: it cost me a bloody fortune. In the flesh I loved it and built it up with all the trimmings.
Would I be wrong in buying at a "low" price. In a word: no.
You know nothing about the person selling it. Maybe they need the cash quickly. Maybe they have more money than they need and want someone else to benefit from this frame. When I moved over here I gave away a couple of thousand pounds worth of stuff on freecycle, on here, to friends, relatives, colleagues, friends of friends etc. Were these people wrong to accept my generosity? Does it make a difference if money changes hands? If so, at what point does it make a difference? £1? £10? £100?
Not all sellers are sophisticated: they don't know the value of what they're selling, and can't be bothered to find out what it might be worth. More fool them.
Not all buyers are sophisticated, either.
Plus, there has to be a difference between the buy price and the sell price for anyone, anywhere to make money.
I haven't even touched on value. How do I know it's worth 1200+ euros? Am I a sophisticated buyer? Am I sure? If I saw a Klein Attitude for 500 EUR I'd think it was a good deal, but I couldn't tell you if it was pre-Trek, post-Trek or a re-badged GT Karakoram.
Clearly, this is based on me being comfortable that the frame is not stolen, or that I'm going to send this seller a cheque and never see the frame.
I hope you don't cancel your account. You sound passionate enough about losing something bike-related that you'll fit in well.