There are many ways you can post the advertisement on blogs or website. Here are some of the common ways:
1. Affiliate Marketing - In this type of marketing you take the banner or text link ad and put it on your website sidebar or post or any other space. When user clicks on those ads and purchases the product, then you get the commission. Commission can be from 10% to 50% depending on company.
2. Banner Ads - In this type of marketing, you are asked to show the banner of brand for some specific time. For example, one month of banner impression time. You make anywhere from 10$ to 300$ depending on your popularity and the brand that wishes to show banner on your page.
3. List marketing - In this type of marketing, your company link or the banner is added into social media posting, or email newsletter or forum post. And this way the advertiser can reach more visitors.
These are some of the common ways in which the people can post the ads on their own blog or on other websites. As a publisher the amount of money that you can make is very variable. As an advertiser the amount of traffic and people reach for your product is also variable. It takes a lot of practice to earn money through such advertisers and methods. If it works you are then you can get a lot of money. And if it doesn't work then you'll earn few dollars that barely helps the expenses.