I think most singles sites I have seen have a free trial initially, and eventually you need to pay money. .
I DO know of a couple sites where you can stay on there for free, but can't initiate contact.
On those sites, if you're online when someone else is who likes your profile, they can send you an IM (instant message), and you can chat with them without being a member, but you can't initiate contact except to send a "smile" or a "card", where you usually can't put in much personalized info, and you can't put in any contact info. .
sites I have been to and liked were: singlec.com, christiancafe.com, relationships.com, and, to some degree, yahoo personals. . .
by the way, IGNORE anyone who calls you desperate. .
you don't have to be desperate to want to meet Mr Right or Mrs Right.
Anyone that calls you desperate cause you want to find a quality mate is just a jerk.
Ignore people like that.