I've told you in the past how to market your business for free, and that's still a good way to get things rolling. However, at some point you might find yourself paying for ads to increase your business' reach.
At that point, you're going to run into one of the big debates in the advertising world: CPC vs. CPM. Aside from both being acronyms related to buying ads, there's a world of difference.
CPC stands for Cost per Click while CPM means Cost per Mille (mille = thousand). Both have their place, but not for every situation.
Before I explain how they work, though, a bit about how online ads work in general.