There are a lot of Kalaris in Kerala where both Kalarippayattu and Marma (Varma) Kalari is taught, especially in northern Kerala. However, learning for free might be a problem.
In most cases there is only a nominal fee that is charged. Most of these institutions are run as tradition and not as money making institutions. The question is very similar to asking whether you can get a gym membership for free.
Pay the nominal fee and learn the art.