How far can i haggle?

[Stangas]

I want a keg system, and the local bloke wants $399 for 2 kegs with all the gear but has a pluto gun style tap.

I want a fridge mountable tap, so i said i would find what i was looking for and then get back to em.

Soooo.... how far can i push him for prices. From what i have seen, there wont be much movement.. but one's gotta try.

Cheers