Funnily, the post inmediately above you (posted a bit later) mentions:

"I had to spend USD15 to run 8 medium EC2 instances for 16 hours to only find 200++ million hosts"

https://news.ycombinator.com/item?id=5406233

and another study was done using EC2 instances:

https://news.ycombinator.com/item?id=5405483