To be honest, online available free resources are more than enough for preparations!
However, using them as the only mode of preparation works only when you have a reasonable base already, and you are a go getter - One who doesn't need external pressure to study
But, if you are the kind of person who needs an external push to study, then I would suggest you to enrol in any coaching with regular classes and doubt sessions to keep you in pace.
As for the fact of Online vs Offline; you can also use the same criterion to decide.
Offline for the latter cases...
Which coaching to join? Read at https://telegram.me/QuantSenseiMain/390
