The app is ad-supported, but since it's free, I can live with that.
By continuing to answer questions, you actively update your profile, which leads to more views.
The cost is .95 for one month, .85 for three months, or .70 for six months.
If you have no interest in casual dating and are looking for a more meaningful relationship, you may want to subscribe to a paid site.
You can generate and validate credit card numbers directly from the app, making it easy to use on the go as well.
Validation in particular would be useful if you were accepting credit card payments on your own site and wanted to make sure the cards were legit.