Most of these offer free trials - if you are meaning free group chat. All have free membership/signups and convert VERY well:
AdultActionCash (AdultActionCam)
ClickCash (iFriends)
Epic Cash
JoYourself
LiveJasmin
MoneyTree (Streamate)
PayServe (Seventeen Live)
PrivateCamZ
PrivateFeeds
PussyCash (IMLive)
SexMoney (AmateurDatingCams)
StreamRay (CamGirlsLive)
WEGCash (VIPStream)