I have some servers I use for file hosting service.
File hosting is just disk and network so the CPU's are mostly idle so I can mine on them at low priority and its free since I am already paying for the servers, $300 was what I calculated based on hash rate of one server x no. of servers, but when I check in November it would have been $1000+.

I just wonder if there is another coin that would earn more?
Sure I can install a bunch of them and get the hash rate but I figured someone here would know.