The price looks good because all the standard options in the dropdowns (the defaults for the low base price) are relatively sub-par such as PVC tubing that tastes like rubber and brass shanks. Once you upgrade everything to the long lasting premium options, the price is comparable to everywhere else.
I don't offer any one-click kits, but you'd only need a few SKUs to arrive there.
One reg
https://www.brewhardware.com/ProductDetails.asp?ProductCode=CO2regulator742-02
One CO2 hose:
https://www.brewhardware.com/product_p/co2hosekit_ffl_ffl.htm
One Manifold:
https://www.brewhardware.com/product_p/co2distrib4mfl.htm
Four ball lock hose assemblies:
https://www.brewhardware.com/product_p/co2hosekit_bl_ffl.htm
Four faucet kits (select Intertap SS, 3" shanks, and ball lock couplers in the dropdowns)
https://www.brewhardware.com/product_p/faucetkit.htm
That system gets you four connections and all the metal components that touch the beer are stainless steel. All connections are MFL instead of barbed so it breaks down easier for cleaning and reconfiguration. All it, it's under $400.