I'd say your best bet is to sell it on theme forest. You can get like $10-20 per sale for that hopefully (excluding their take). But selling typically, honestly I don't think you'll get that much.
While the theme is simple, its what a lot of new web hosting companies are after these days; a clean, simple look. I think its worth more than $30 if only one was sold. However, your best bet is definately to try and sell it multiple times for a small amount of money. Try and sell each copy at around $20.
He is right, its really a simple design...and would be better if you make the plan boxes large and only 3...
I really like http://www.macalicious.com/ as far as design goes, it's got a really nice feel to it. Less is more, look at Apple's website, take a look at http://bell.ca/home/ I think it's incredibly hard to have excellent design using a pre-made template because design has to fit like a custom tailored job. In order for a theme to be worth 100$, it has to offer either customization, or plenty of behind-the-scenes customization abilities like Arthemia for Wordpress. I mean, it's not just a wordpress theme, but an entire theme engine with built-in plugins and extra configuration pages. And that's only 70$.