Do you think that you should spend some of your blog budget in search engine optimization. Well if you ask for a honest answer it totally depends on you. You are the one who decides whether you have enough traffic and revenue to spend some in advertisement. SEO is best for your blog if you think you can carry on with your blog, as a matter of fact there are a lot of blogger blogs which comes on the first page in Google search but the admin don't follow his/her project. People often think of pay per click (PPC) as a temporary measure. It's just there until the SEO campaign achieves the rankings you're looking for. But, there is no reason to stop PPC once you're on the first page with organic SEO. The double branding effect you have far outweighs the potential that you're paying for a click that you could have gotten for free. Here's the thing, the tracking you can do with PPC allows you to track everything, down to a minute level of performance. This allows you to tweak and test your PPC campaigns to ensure every dollar you spend makes more than a dollar in return. That, of course, means profits. As long as your PPC campaign is profitable, there is no reason not to keep it active.
And, since only about 30% of searchers click on a paid ad, you're really not in significant danger of losing the "free" click.