I want to get an HPS light.
Why? because HPS provides more yellow/red light and blue light is very easy to supplement with Fluo.
Besides I know it's strange but I really like the orange glow of HPS.

I'm looking to buy the GE Lu400 (street lamp hps) and adding a T5 54 watts Actinic 03 tube.

My question is would this setup be better then buying the expensive HPS grow lights.
I know that with an extra T5 fluo I'm adding more watts but I'm convince that this setup would provide a better spectrum at a lower price.

I really fail to see the advantage of buying the expensive HPS over the cheap (20$) GE Lu400.

GE Lucalox LU400

Actinic Blue

Sun Master

To clarify, the Lucalox spectrum is the $20 lamp that you wish to purchase over any one of the four "Sunmaster" spectrums that are above?

I've only read about HPS (I use fluorescents at this point), but I think that you're quite correct. If the Lucalox is widely used for general lighting, the sheer volume will help to create a lower price. There seems to be a hefty surcharge for anything labelled "grow light." And heck, the red spectrum on it (supplemented with your blue) looks better than any of the last four.

Looks like a wise decision to me.