Smartsheet is a project management and collaboration suite that visually and functionally resembles Excel or other spreadsheet based tools. This approach gives Smartsheet the advantage of familiar interface, but also severely limits its social collaboration and team communication capabilities, as well as makes customization of the product impossible. If you are looking for a free Smartsheet alternative with better collaboration capabilities or the one that you can host on your server and customize, Bitrix24 probably makes a better sense, especially considering a number of worktools provided for free.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.