Sponsored posts work much in the same way as paid guest posts, but they are posted by big businesses instead of individual bloggers. Therefore, the scope for fees is much higher, as businesses have larger marketing budgets than humble bloggers. Having sponsored posts by large companies will also help promote your site as reputable and as a leader in its field.
Keep in mind though, you don’t need a website to do sponsored content since you can also get paid if you have a lot of social media followers. My wife has a pretty big Instagram following, and she gets all kinds of sponsorships. Not only does she get paid in cash, but we get a lot of free stuff, too. We’ve received free rugs, free lights, and free carpet cleaners. She only promotes things she loves though, so this strategy works really well for her. /injects>