In here they stayed free for several years, but in the end they started charging a service fee at around mid-2014. They penalized the lack of anticipated planning, i.e. the earlier you made a reservation, the less you paid. Likewise, if you were planning for the following day, you would pay the most, regardless of how many travels were being advertised for that day. I don't know if that's the price scheme still today, I haven't used it since then.
There was a big movement of users to Amovens and similar clones. And, some big Whatsapp groups were created by people who do some trips regularly and wanted to avoid paying. Still today some of those groups exist, they are almost always full (max. 250 people or so in Whatsapp groups) and there are waiting lists of people interested in getting added. I assume similar groups exist in Telegram.