Usually they only sell per month, but I have been allowed to sell on CPC or CPM. Basically I take over the spot, and resell it on CPM and CPC.

The site has around 15 - 20K visitors a day, with many being from the US. The banner will be placed in each article below the first paragraph.
CPM bidding start at $2 CPM.

Tons of targeting options, including re-targeting.

https://coinpedia.org/