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Comment by mort96

3 hours ago

I don't understand this line of reasoning. I don't do auctions, but if I did, it would be because I want that item. When I want something, I never have an absolute hard price ceiling; if I'm willing to pay $10000, I'm willing to pay $10000.01. I can't imagine anyone who would be happy to pay $X for an item but not $X + $0.01.

Like, if I'm at a store and an item costs $500, and I bring it to the checkout and the cashier says "oh sorry that was mislabeled, it's $500.01 not $500", there is no world in which I go "okay never mind then, $500 was my max". There does not exist a situation where I've decided I want something at price $X, but would not buy it at price $X + $0.01, because $0.01 is absolutely negligible.

So where does this fantasy of an absolute max price come from?

Your max price should be the price such that you're indifferent between buying the item at that price and not buying it at all.

At a shop, usually you're paying less than the maximum you'd be willing to pay, because the shop's prices are fixed and it would be a big coincidence if the price they set happened to match your max price exactly.[1] So even if we model you as homo economicus, it's normal that you're almost always fine with paying $X + $0.01.

In the case where $X really is your max price (i.e. it's right at your threshold of indifference), the idea of rejecting $X + $0.01 seems less silly. You were already very close to deciding $X was too much, so you're probably feeling ambivalent about making the purchase, and the trivial nudge of an extra cent being added to the price might as well be what pushes you over the edge.

[1] There are exceptions, e.g. when you have a negligible preference between brands A and B, so you're defaulting to brand A because the prices are exactly the same, but you would buy B if it were marginally cheaper. But that doesn't affect the main point here.

  • I don't see why I would buy something if I'm indifferent to whether I buy the thing.

    • So it should be the highest price such that you're not indifferent, you marginally prefer to buy it. The point is that you're right at the threshold where it's just barely worth it to you.

      3 replies →

It's not supposed to be some red line absolute max price, but rather "how much is this item worth to you?" You set that as your max bid price. If you get it at auction for less than that, you got a good deal, but if you buy it for more, you got a bad deal. If someone outbids you, then maybe it was worth it to them, but you (supposedly) would not have wanted to buy the item for that much, and would rather use your money for something else.

For tricky-to-price items like unique art pieces, the idea that you can pin this down might be a fantasy, but for commodity items it's pretty reasonable. If you can buy the same thing at costco dot com for $500, then it's probably not worth more than $500 to you, and if at auction you get outbid and it sells for $500.01 then you'll shrug and go order the same thing for a cent less, having wasted only a few minutes of your time. If the item you're bidding on is discontinued (e.g. it's last year's model) but you can buy a slightly better one for $550, and you can spare that extra $50, then again you won't be too sad about getting outbid. Online auctions are more popular for used items, but again in that case you usually still have an idea of what a used item is worth to you.

  • The logic of "you shouldn't ever need to snipe, just bid your max price" only works if we assume that the max price is a red line though. If I "value something" at $5000 (as in I want to buy it at $5000), and I bid $5000, and someone bids $5000.01, I would probably be happy if I sniped them and got the item for $5000.02.

    • I'm not defending "you shouldn't ever need to snipe, just bid your max price" as a hard principle, just trying to explain where the idea comes from. Sniping can be strategic for lots of reasons: you don't have to commit to a bid until the last second (in case you find a similar item for cheaper elsewhere), you deny other people information, you might avoid anxiety from wondering whether your bid will win, etc.

      That said, the max price is supposed to be a price where you are not especially happy to get the item at that price, but not really sad either, a price where you would say "well, I hoped for better but I guess that's a fair deal". That's not realistically pinned down to the cent. But if you set a max price at $5000 and would be happy to get the item at $5000.02 (for some reason other than satisfaction from sniping), then you set your max price wrong, or at least differently from how economists expect you to set it.

it's because this argument of "what is $0.01 more?" can be extended forever, implying you are willing to pay an infinite amount of money for anything. since we know this is silly, we try to understand what our "real" maximum is. this is difficult to do for exactly the reasons you mention in your comment! surely $0.01 is negligible! there is a tension here.

and so, absolute max price is not a fantasy - the world would be absurd if it were - but instead its a real and difficult to construct value

  • It can be extended forever in theory, and sure, that is an interesting philosophical discussion, but it isn't in practice. We're discussing sniping. That means you make the choice once: do I send in a last-second bid that's $.01 more than my "max price", or do I not?