No, there is no additional fee or hidden cost for Mofluid Plugin. Mofluid Free version is free and Mofluid Pro version is available at one time cost of USD 399. For Mofluid Pro users we provide 1 year free support. Installation cost is $49 though this cost is optional as you can install the plugin yourself. To make work easy for you we will provide the installation guide.
Steps to Install Mofluid Free Plugin: https://mofluid.zendesk.com/hc/en-us/articles/200441552-Steps-to-install-Mofluid-plugin-Free
Steps to Install Mofluid Pro: https://mofluid.zendesk.com/hc/en-us/articles/200181492-Steps-to-install-Mofluid-Plugin-Pro