What is RPM and CPM and why do they matter when buying a channel?

RPM (Revenue Per Mille) is how much money you earn per 1,000 video views after YouTube's cut. CPM (Cost Per Mille) is how much advertisers pay per 1,000 ad impressions before YouTube's cut. These numbers matter a lot when buying a channel because they determine how much you will actually earn from views. Finance and business channels typically have high CPM ($10-$50), while entertainment channels may have lower CPM ($1-$5). Always ask for the channel's RPM and CPM before buying to calculate your expected monthly income.