Microsoft Lync is a popular enterprise messaging, groupchat and videoconferencing solution. The basic version for the cloud edition starts at $2/user/mo if purchased with Office365 with a five-user minimum, and goes up to $10/user/mo if purchased separately. Lync server pricing is rather opaque, but it generally starts at $3,600 per server and with extra per user/device licensing, integrations and features, you are looking for a price tag of around $10,000 or more for a typical on-premise deployment. Unfortunately, even server edition of Lync can't be used for telephone calls or CRM without additional work. If you are looking for a free Lync alternative that you can use in cloud or self host, that provides group chat, videoconferencing, supports incoming and outgoing phone calls that are passed through your CRM, if necessary, Bitrix24 makes a great choice.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.