Alright, I am new here, I am going to try and explain this as well as I can.

I have a product that I paid 22.50 for. It was 280 watts with 1 rail at an efficiency level of 85. Now I have deduced the cost per watt, that was easy. However I am trying to find a constant (I guess). If I am paying .08036 per watt, how can I find if I am paying to much for a product. There are multiple levels of efficiency (85, 88, 90, etc) and you can have any number of rails (1,2,3, etc) that would come apart of the equation.

So, is there a constant that I can say, with x rail and at efficiency level x and x watts, this is what the price should be at.

I hope I explained this well. If you have any questions please ask. Thanks for your time.