How do I search for other yahoo messenger users that I can IM without them being in the personals?

I have other messenger users who IM me all of the time. They have seen my "profile" they say, and it has it available for them to Instant Message me on there. I have looked on the personals, but it charges you to join, and then you are able to IM others, and I don't want to do that. So how do I find profiles, or whatever these guys are talking about, in order to IM them if I want to talk to them?