Don't get discouraged and don't read any HYPE systems that tells you that can make a fortune with blogging, however concentrate, plan and stay focused. 20 bugs are a lot of money from blogging most bloggers never make even a dollar.
You will know all the answers by yourself, if you know the right questions to ask. I will try to help you.
1. What is your hobby? What you really like to do? (That's your blog niche)
2. How much time and effort you can spend?
3. How much you want to make from this blog? (be realistic, this is your short term goal)
4. How to achieve this goal? (Methods of promotion)
5. How much you are willing to invest?
There are very other things that need to come to consideration - choice of technology, products to promote, going broad or attacking small niche. As well as good competitor analysis.
Investing in domain name, well it is $10, you can get reliable hosting where you can host 10 blog for about $5 month. So far you've made $20 on Blogger, well if you have 5 blogs which make $20 a year each (of course you can make more) you will double your investment!