That's the wildcard aspect of an estate or yard sale. Some parent says, "Meh, I guess my kid will like it" and think that $50 for a used kids bike is outrageous. While at an auction, a few nostalgia buffs could get into a bidding war over it, especially that cool gear shift bike. Even considering the auctioneer's portion of the sale price it might be a better deal. 80% of $100 is better than 100% of $50. Depends on the caretakers of the estate, too. Do they want maximum profit or do they just want to liquidate everything quickly.