That's not to say they don't have their uses, but they will not handle much traffic unless its heavily cached (but then you only have so much memory).
If you have a blog that is static and uses external js components for things like comments (disqus), you could use it in conjunction with cloudfront to handle quite a bit more traffic. Most traffic would be routed via cloudfront. Admin panel would be handled on a subdomain.
A three year reserved instance would be significantly less than $60 per month. The upfront reserve price of $300 over 36 months comes out to $8.33/month. Throw in an approximate cost of $14/month for the use of the compute time, EBS, network traffic.
That brings your monthly cost to just under $23/month, for a grand total of nearly $830 over a 36 month period.
Amazon EC2 Micro instances have very poor performance - sure they have 1.7GB Memory but they have shocking performance. Not worth the price for small websites/blogs.