Should I offer advertisement space?

I just have a question for other bloggers. As you read on my post title, should I offer advertisement space for this blog? I have seen other bloggers offer ad spaces on their blogs. I was wondering how successful it is to sell your own ad space(s) without using any company(middleman). I definitely would like to increase my online income and thought that offering some ad spaces on my blog at low cost might work for me. Please leave me some comments/suggestions. I would greatly appreciate anyone's comment on this topic. If you sell ad spaces on your blog, please let me know your blog address, so that I can visit and see how it is done. Thank you for your help in advance!