Looking for someone to date can be as expensive as actually going out on one.

Subscribe to an online dating site and you can easily pay upwards of $40 per month for membership; you'll pay more if you also want personalized coaching and other features to improve your odds of finding that special person. That adds up: The market for online dating is expected to reach $1.6 billion by 2013, up from $957 million in 2008, according to Forrester Research.

With online services reporting an increase in subscriptions, sites could raise their prices without losing customers, says Mark Brooks, principal consultant for Courtland Brooks, a consulting firm that works with the online dating industry. "By all accounts, online dating sites are leaving money on the table," he adds.

If you consider signing up an investment in your future happiness, be sure to do your research before shelling out any cash:

The Freebie Strategy

In the You Get What You Pay For category, PlentyofFish.com and OKCupid.com, among others, let you troll for dates free of charge. There are plenty of prospects choose from, but members may not be as dedicated nor the features as sophisticated as those of a pay-for site, says Julie Spira, author of "The Perils of Online Dating."

Check site traffic

Ignore dating-site boasts about their number of profiles. Most sites offer free profiles -- it's communicating with other members that requires a subscription. "The real measure of a dating site is the number of people who have logged in," Brooks says. Use analysis site Compete.com for a rough estimate of monthly visitors. The higher the number, the more active the community and the better the odds you'll find eligible members able (and willing) to respond to your messages. A paid subscription isn't worth it unless monthly traffic is at least 10,000 unique visitors, he says.

Read site reviews

Complaints about dating services rose 62% from 2005 to 2008, according to the Better Business Bureau. Read consumer reviews about a site and review its Better Business Bureau record before signing up, says Jeannette Kopko, a spokeswoman for the BBB in Dallas. One of the most common complaints: subscription charged that continue to show up after you cancel membership. "If you don't cancel in just the right way, it auto renews your subscription," she says.

Buy a package

A month-to-month membership is the most expensive option. At Match.com, for example, you'll pay $40 per month. Other options include a three-month bundle for $23 per month (save 42%) and a six-month bundle for $20 per month (save 50%). Brooks says six-month increments tend to be the best deal offering enough time to find someone before renewal and a substantial-enough package discount that you won't lose too much money if you succeed right away.

Wait for coupons and sales

Like any other purchase, online dating has sales and coupon codes. Chemistry.com is currently offering three months for the price of one, a $50 savings. Use coupon code "GEEK" at Match.com and save 25% off membership.

Sites also regularly host "free communication weekends" that let non-subscriber members reach out and respond to other people on the site, Spira says. That's usually a subscriber-only feature, so signing up or revisiting a site during such promos can help extend your membership.

Avoid sweetheart scams

Scammers prey on online daters reeling them in with promises of love and then begging for cash to afford a plane ticket or other expenses. Sites have policies in place to weed out such users, reviewing profiles and communications for red flags, such as poor grammar, mismatched photos and details, and keywords including "wire money," Brooks says. Some also use monitoring services that recognize the scammer's computer preventing him or her from creating a new account after one gets flagged.

Still, remember that merging finances isn't something you should do before the first date. "Don't ever give money to somebody you haven't met," Brooks says.