For one, a vote is a right. It costs you nothing to vote. A vote has a single purpose.
Buying an item is not the same. You have a fixed amount of money and there is an opportunity cost to buying anything. Moreover, you need to buy certain items to survive.
If you are poor you are not in a position where you have a choice, you have to buy the cheapest items that you need to survive. If you are rich you have more than enough resources to survive, to buy the items you actually want, and more beyond.
When you are forced to vote in a certain way because you cannot afford not to, that is not democracy.
It's an analogy. There's also an opportunity cost to a vote, insofar as casting a vote for A means you can not cast a vote for B. You also have a fixed amount of votes, 1.
> If you are poor you are not in a position where you have a choice, you have to buy the cheapest items that you need to survive
This is a really dull and tedious way of looking at things. Poor people make choices based on preference all of the time. Especially because food in the US is dirt cheap in historical terms. Sure you aren't buying organic grass fed meat, but you can pick from a wide range of cheap foods. Are your choices more limited, sure, but you still have choices.
For one, a vote is a right. It costs you nothing to vote. A vote has a single purpose.
Buying an item is not the same. You have a fixed amount of money and there is an opportunity cost to buying anything. Moreover, you need to buy certain items to survive.
If you are poor you are not in a position where you have a choice, you have to buy the cheapest items that you need to survive. If you are rich you have more than enough resources to survive, to buy the items you actually want, and more beyond.
When you are forced to vote in a certain way because you cannot afford not to, that is not democracy.