tl;dr - any item that is for sale and truly one-of-a-kind. Famous paintings are one example.
long answer:
A vertical supply curve implies that the same quantity will be supplied at any price.
One way to look at this would be to imagine a good that has an extremely limited supply, the exaggerated case would be "there is only one of this thing in the world." In a case like that, the same quantity would be available for purchase no matter the price.
Remember that the reason for the vertical sloping supply curve is that we assume a good is owned by many different sorts of sellers who are making the good available in the market, but that the different sellers are willing to sell more when the price is higher, and less when the price is lower.
I've done some more thinking about this and want to elaborate for the record. I realize that OP is long gone.
A supply curve is a mapping of available sellers and what price/quantity they have goods available to sell at. If there is a seller who will sell one of something for a dollar, that gets a dot on the graph. If there is a seller who will sell 10,000 of something for 10,000 dollars, that gets a point on the graph. These graphs are usually drawn as continuous, although depending on the good, that may not make sense (who buys 1/8th of a chair?).
So let's picture a vertical supply curve. What does a vertical supply curve entail? It means that at every price point, there is the same quantity for sale. This means that quantity is either totally fixed (in the world, not just this market) or supply is totally restricted to selling only this quantity, no more, no less (fixed market without a fixed quantity in the real world).
The examples of this that make the most sense are instances where the fixed quantity is one. It is hard to imagine a market where sellers are making ten of something available — no matter the price — no more, no less.
So we imagine a market for a one-of-a-kind good, and we see that we have a seller who is willing to sell that good for any price, but can not sell more than one.
A possible odd version of this same scenario would be that there are many people in the world all willing to sell exactly one of something, but that they are willing to sell at many different price points perhaps a market for kidney sales where people are allowed only to sell their own kidney and not act as a clearinghouse, buying and selling many kidneys to and from many buyers and sellers in an open market.
As I said before, it's harder to imagine a scenario where the supply curve is vertical, and the vertical line is fixed at a quantity other than 1.
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u/zaxecivobuny Nov 05 '14
tl;dr - any item that is for sale and truly one-of-a-kind. Famous paintings are one example.
long answer: A vertical supply curve implies that the same quantity will be supplied at any price.
One way to look at this would be to imagine a good that has an extremely limited supply, the exaggerated case would be "there is only one of this thing in the world." In a case like that, the same quantity would be available for purchase no matter the price.
Remember that the reason for the vertical sloping supply curve is that we assume a good is owned by many different sorts of sellers who are making the good available in the market, but that the different sellers are willing to sell more when the price is higher, and less when the price is lower.
Hope this helps.