Probably around 350 for all kegging hardware and a temp controller. Add on if you upgrade to perlicks or all stainless. Building materials (2x6, silicone sealer, stain, sealer, appliance paint) probably about another 75.
Just my two cents: You can do it in stages or go all out. Just do it the right way the first time so you do not question or wish that you done something more later.
I originally was going to do mine the same style as your picture, but I thought that I would kick myself later for not doing another Jester ripoff. I am glad I went the way I did.