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

RPM (Revenue Per Mille) is what you actually take home per 1,000 views after YouTube's cut. CPM (Cost Per Mille) is what advertisers pay per 1,000 ad impressions before that cut. Both numbers matter a lot when evaluating a channel to buy, since they directly determine how much real income a given view count translates into. Finance and business content tends to run high CPM (often $10-$50), while entertainment content usually sits much lower ($1-$5). Always ask a seller for both numbers before buying so you can calculate realistic expected monthly income rather than estimating from view count alone.