1. an expression of elation or agreement at something that causes excitement.
2. a term to be repeated when someone succeeds at a task or says something of wit; another way of "giving props" to someone.
3. a line that can be used to express interest in someone, similar to "How YOU doin?" or "Wassup giiiirl!"
4. what you ask someone when they really want Doritos.
Origin: The expression originated from instances in which someone at a party would make an alcohol run and would ask others what they wanted them to pick up. Literally, "What do you want from the store?"
In other words: "Whatever it is that you want from the store, I got it or will get it for you"