Ask HN: Going free to cut costs/get users?

A client of mine has a niche dating site that has been up and running for about a year. It's gotten a good amount of signups and press exposure, but has been having trouble converting people to paid customers (probably a chicken-and-egg problem).

He's running the site on his day job salary, so he's thinking about making it completely free for a few months to cut down on costs (PayPal Pro, Recurly, etc.) and try to get the user count up, while allowing me to focus on non billing-related things like making the site better, tighter Facebook integration (I just switched it over to the Facebook Registration Tool for signups), and refactoring code.

We think the possibility of spammers taking over the site shouldn't be too much of a problem, since we've cut spam significantly by using CloudFlare and other services, and we plan on rate limiting people who haven't been verified by Facebook, so are there any other foreseeable pitfalls to doing this?