I would say it all depends on who your working with.
A great company I've worked with recently has been Exotics by Nature. They are MORE than willing to get me what I want and at a great price. Truly awesome guys over there. I've got a bp from someone on fauna and they threw in a freebie male. It really depends on who you work with. Maybe you just havnt found a flexible person yet.

I agree though that a deal shouldnt be in your mind all the time. Bps are NOT cheap. And quailty wont be cheap. Depending on what morphs your working with it can be very insulting to the breeder if you low ball them. I'm all about giving on deal on my bps I sell but if your offering $300 under my asking price, thats a bit much. (as an example)