I found a rather original website that offers some funny cartoons that you can post on your blog without paying anything. I think that using images is a good idea for bloggers, as some people are a lot more responsive to images than to text. Actually, I have seen a cartoon from this website on another blog, and I thought that it was quite funny. I just want to give an example how you can incorporate such cartoons in your posts:
I am sure that a lot of your readers will like the cartoons.