Let's assume that I am selling an apple. I haven't decided what price it should be sold at. And you want to buy the apple so you bargain with me. You could have bought it with $1, but you want to save more, so you ask me :"could I buy this apple with $0.5"? If I say "no", then you will further say "how about $1?"—— in a word, you don't make your best offer at the first time. You hide your real proposal behind for less cost.
Is there any word to express such behaviour ?
Update: Well, I didn't expecte so many people answered this question~ I have read all the answers. All of them are not wrong. It's my fault that I didn't describe my question clear enough. So I now add more details.
Actually, I ask this question because when trading, I always stand on my bottom line to make my best offer——If I think an item is worth $10, I will propse an offer that worth $10 and if I am asked to pay more, I will decline. While some traders hide their bottom line. For example, one may think my item is worth $10, and he attempt to exchange his item worth $5 for mine. However if I ask more, he would also accept my proposal, i.e., he doesn't make his offer best at the begining. I hate such behaviour but I don't know how to describe it. Here I learn the word "bottom line" from the accepted answer, so I can write a sentence on my trading profile: "Stand on your bottom line to make your best offer, please." Perfect.
As for the words "haggling", "bartering", "negotiating", etc... I think they have the similar meaning and can all answer my original question well, but didn't meet my real intention, which I didn't describe clear previously. I appologize for that, and thanks all~