I don't want to come across as insulting, but I'd recommend a different pricing strategy. Instead of focusing on the price, focus on the advantages/differences of Strapfolio versus other themes. What does it do differently? Why did you make it? Sell its simplicity: more features != more value when you're talking about website themes.

But don't reduce the price (yet). I'd be surprised if $30 (or even $40 or $50) would be a barrier to your sales. You don't know yet either, so why lower your price? If it's not worth $50 yet, what can you add to it to make it worth $50?

Incidentally, WooThemes (linked above) will charge $70 to use their portfolio theme, and they sell a whole lot of themes at that price.