You thinking of a custom watercooling system where you build the loops and tank etc? Or just a pre-built 'block' one that just attaches to the processor? ~
Scratch all that, my sleep deprived mind just noticed your budget, defo go custom loops in that baby. I guess I am not the best to suggest much as I am a total budget freak and no the good 'cheaper' things to get haha.
I HIGHLY recommend a Phanteks case tho, I have the Enthoo pro, their budget version and it has massive space for cooling, and loops for when I want to one day upgrade to water cooling. I think The Entho Primo would be right up your alley. It has ample space for any of your cooling needs and retails at roughly $200-250 http://phanteks.com/Enthoo-Primo.html