What is the likelihood of gaining traffic to a free blog site through good SEO?

As the title says, i wonder how much traffic could be gained through good SEO tactics? I'm thinking of starting a mmonfruit page or the likes of to start a blog based around a topic i think i could do quite well in. But would the resuts be better say if i paid for a site name and hosting?
Thankyouplease.

See original post by elchubinebrae