Thanks, as I can say now it will be work out of box with any marketplace item uses online subsystem of UE4 (Without custom modifications but as I know Allar’s Generic Shooter is pure blueprint so It will be work out of box). Not sure about the price but (subject to change) Min: 50$ Max: 100$
Because this is not just a plugin with C++. There is a web admin panel, C++ plugin with integreates UE4, also will be some applications (services) for matchmaking, chat system etc… So I can’t exactly say the price but I want to sell everyone so price will not too much high. Also can’t give a exact time but as I can say development going fast 
(currently my only job.)
Thanks 