It varies for the actual gaming website, usually with how recent (and hence popular) the games can be. For my gaming sites, it's usually $3.00 - $4.00 on a good day. Gaming keywords, especially flash gaming.. don't seem to be that high paying these days. eCPM is: (Total Earnings / Total impressions) * 1000.. So total number of earnings divided by total number of impressions in the thousands.
eCPM is just an estimate cost per thousand impression WHich mean that this is the estimate earning every 1000 impression you get based on the current status, mean it will keep on chaging Your CPC and number or click will directly affect your eCPM. eCPM = (CPC X number of click / total impression) X 1000