I’d be inclined to kill two birds with one stone… like this.
Wordpress website --> Unbounce landing pages published to it.
Focus on building good quality landing pages and A/B test to a reasonable conversion rate, publish these landing pages to your Wordpress website so that essentially you are improving both your website AND landing pages at the same time. Make them an integral part of your site and benefit from the better-performing landing pages across the board.
AJ is right, however as with all start-ups on a limited budget, the priority is almost always getting leads, sales and customers, ultimately increasing revenue and cash flow. Having a pretty website is all great but not all good looking fancy websites generate business, in fact, a lot just simply don’t. I’m of the opinion that unless you’re running an information website virtually all pages on your site should be considered “landing pages” and should have the same conversion optimised principles applied. That way you’re looking after the heart of your business before making it look fancy. It’s easier to make a good performing landing page better looking than a good looking page that’s under-performing suddenly soar.
That’s just my approach not everyone will agree but to me it makes sense.