Welcome to thefret.net tung...
Welp, As far as how much.. that depends.. I thought this is the American way.. put a few bucks in a product and charge for it..
You also have to make an enclosure.. and have a female or male plug depending on design.. you have to buy in quanity if you really want anything cheap.. you have to add in shipping..and then there is the "labor time" making it...
I been searching for a dummy..ummm.. and find that I am not the only one.. many sites just say as you did..make one.. but that leads me to believe there are many people out there looking for one already made.. I personally feel its worth someplace between $15.00-$20.00 made.. ready to use.. and if its that cheap to make.. why isn't someone doing this?
I went to mouser..looked up 16 ohm 25 watt resistor just for the heck of it.. it came back with like 1000 different ones.. which at that point I was lost.. sigh... I probably will have to break down and make one from designs found on the net.. just suprised they are not already available.. there is a thing on e-bay..more of a attunator type, its around 50 bucks.. I might actually buy it before building my own.. just out of lazyness.. again an American way..