Difference between "kaufen", "einkaufen", "aufkaufen" and "ankaufen"
Same as buy in English. Works for pretty much every situation, from chewing gum to real estate to bribery ;)
Needs an accusative object, e.g.
- Ich kaufe einen Apfel.
- Er hat ein Auto gekauft.
This leans more towards shopping ("einkaufen gehen" = "to go shopping"). As a noun it is also often used in the context of a corporate purchasing department ("die Einkaufsabteilung", "Sie arbeitet im Einkauf.").
Can be used with an accusative object:
- Ich habe Hundefutter eingekauft.
Note that "einkaufen" doesn't need an accusative object:
- Ich gehe heute auf dem Bauernmarkt einkaufen.
Another meaning of "einkaufen" can be to pay money to attain a certain status that is usually inherited or achieved through merit, e.g. to acquire an aristocratic title:
- Er hat sich in in den Adel eingekauft.
Similar to English usage ("to buy up something").
Needs accusative object in most cases:
- Der Sammler hat alle verbleibenden Exemplare dieser Ausgabe aufgekauft.
Is also used in the context of company acquisitions. The company being bought is usually the subject and the passive form is being used:
- Skype wurde von Microsoft aufgekauft.
Usually used in the sense of someone offering money for certain (used) items, e.g. (dental/jewelry) gold ("Goldankauf") or used cars ("Ankauf von Gebrauchtwagen").
Needs an accusative object:
- Der Gebrauchtwagenhändler kauft gebrauchte Autos an.
very good information and cleverly styled, +1 for that. The only thing I'd like to reassure myself of: "Ich gehe auf dem Bauernmarkt einkaufen" versus "Ich gehe auf **den** Bauernmarkt einkaufen"? The first one is if you're already there, the second if you plan to go. I think you wanted to use the second although both are correct :)
In this particular example, both have about the same meaning and neither indicates that the speaker is already there. The second has a tiny bit more of an emphasis on the place / direction. It is possible to entirely omit "einkaufen" and it would still be a perfectly correct sentence (though it would leave us guessing what the speaker is planning to do at the farmer's market): "Ich gehe auf den Bauermarkt."
That last one should have been spelled "Bauernmarkt" (with an 'n'). Don't want anyone to learn an incorrect spelling here ;)
"Ich gehe auf dem Bauernmarkt" would also be correct. Slightly strange-sounding, but (IMO) correct.
Grammatically, yes. It means that you're engaging in the activity of walking on the farmer's market. Sounds strange, though. If you intend to say that you are engaging in a leisurely stroll across the farmer's market "Ich gehe über den Bauernmarkt." would be a much better alternative.
Nice explanation. One could add to "aufkaufen" that this implies in most cases that after that the remaining offers on the market are considerably reduced if not zero.
Very good - one could mention the fact that "einkaufen" is giving money for something while "verkaufen" is the complementary action giving something for money. This seems to be an important difference to english, where there is a separate word for the latter activity.
I would suggest using an *einkaufen* example without *gehen*, just to stress that it can be used by itself. E.g. ‘Mein Name ist Lohse, ich kaufe hier ein.’ Other than that great answer. +1 +silver badge ;)
Re: einkaufen / attain status. While true, you are scoping this too narrowly. It can also be used for paying money in order to become part of sth. that can only be attained by actually paying money, e. g. _in die Firma einkaufen_ for buying (a significant amount of) corporate shares of one company, usually in order to be able to influence it.