The Genesis theme framework by StudioPress is robust and easy to use. While there are premium plugins that can help you build a landing page, if you’re already using Genesis, or a Genesis child theme, making your own landing page is a lot easier.
Frankly, landing pages don’t have to be extremely fancy. They need to be persuasive and informative while driving people to that call of action on your page. If you don’t have your strategy down, then your plan to get people to buy something or sign up for something will fail.