Right, NDG is a lite version. Never tryed Coova chilli so im going to take a look.
Another solution wich im goin to try is ZeroShell wich is an LinuxOS mean to handle networks and yes, you can set up and captive portal.
In my case what i really want to do is to set up a captive portal wich every user must click on my JSE banner - see JSEcoin - A criptocurrency that mine a couple of coins for every click and dont need a lot of resources to work, very lite.
This way i give "free internet" and i monetize trought this coin.
To a more deep understanding take a look at their web.
So, to everyone that is interested on this proyect maybe we can make it work.
EDITED: @rogerio24 okey i found a stunning solution . OPNsense. Just check the Captive portal features. https://docs.opnsense.org/manual/captiveportal.html