Theme Marketplace.

Hi,

I am thinking of creating a Theme marketplace, similar to themeforest but only focusing on wordpress, drupal magento themes to begin with.

I want to stick to a tight budget, as I know that this will take time and effort, which is fine. So i looked at taking a MVP approach detailed below.

I would love any insight on this.

So I thought of the following,
Launch a blog, with an article a day related to themes and theme development.
Build an audience with pintrest and other social media platforms.
Do giveaways and competitions.

Monitization of blog to test the idea before building an actual marketplace.

Allow users to buy themes from the blog taking a cut from the theme developers final cost.
So for exmaple if a theme costs $100.00 and I charge 10% I can take $10.00.

But so far the cost of running the blog is
Seo $300 per month.
Article 400 word $15 per article. * 30 = $450.00
Marketing roughly another $200

Are the numbers correct above? As I dont write articles and blog myself, I would be looking to outsource most of this.

the Idea of the blog, is not to make me rich but to simple test if creating a theme marketplace is worth it. As Envato and others charge high rates and I would like to simply undercut them.

thanks for reading, and the comments below.