As already mentioned, the biggest question for you is to decide if you want to use your own domain or not. If you don't mind having someone else control over your content, using a site like medium can get you a lot of publicity for free.

Personally, I want control over my audience so using my own domain is paramount. I use Jekyll + S3 + Cloudfront and have very little cost (<2$ a month) for ~1k visitors per month.

however, having said all that, more important is to actually write!