While we sell some themes on WordPress.com, those purchases can’t be transferred to a self-hosted WordPress site. The main reason is because WordPress.com is a service (you don’t get any files to download) and the code is different to some extent. However, you can ask for a refund from WordPress.com within 30 days from your purchase and buy the self-hosted version of the theme from our shop.
To have a better understanding about the difference between these two platforms, we recommend you to read this in-depth article. This way, you can choose wisely the right theme for what you want to accomplish.