Don't ever buy anything from them. Here is a copy/paste of a support ticket when I called them out on having broken code in their premium themes:
You have got to be kidding me here.
When a user is logged in, the user's avatar doesn't show in the top left of the home page.
No I'm not giving you access, you don't know what you're doing. How dare you sell something that is in such as mess as this,
Want my respect? Earn it by fixing this code. Install that theme your own server and fix it.
We didn't sell you by force, that's why demos are there online so you could check the problems before buying it. Now that demos function is made clear to you, i have sent the issue to the designer and he is looking into it.
Sales and Support Manager
Fantastic reply. This screenshot is going all over the web. It's irresponsible and unethical to sell people such obviously broken code and your response in the matter shows how little you care.