Perhaps you get 1000 (or 1100?) watt power supplies for free, but I don't. It is my understanding that the Prisma does not come with a power supply. The dragon came with PS installed.

I have been mining for years, starting with graphics cards, to butterfly rigs, to AM BE, cube, and all manner of USB miners.

$550 delivered for a complete 1 TH solution running today will do just fine. I have no doubt I can shake a few coins out of it.

PS: There isn't a mining calculator out there worth a crap. That's the first thing you learn as a miner.