If someone wants to learn a new spoken language, which is the best method to learn, go offline and join a good fee batch or go online and take an online batch with a low fee?

In an offline classroom setting, many people learn the language together. It also gives the opportunity to communicate with teachers and other students directly. It can improve someone's skill to a great extent.

On the other had, there are different types of online courses available.

In case of pre recorded courses the students can take the courses according to their time. However, the responsibility of completing the course largely depends on the individual students. How motivating they are in completing the course, without which the course will be of no use.

Then there are online batches which are like virtual classrooms where the students participate in the class together at a given schedule. They probably have to give exams at a certain date and time. Those courses kind of compels you study even if you don't have the motivation to do so. Just like offline classes.

To conclude, it largely depends on personal preferences. Whether the student feels comfortable in communicating to strangers online or feels more comfortable in a classroom setting. Whether the student is motivated enough to held himself/herself accountable in studying the language or he/she needs external motivation to do so. Every persons need and situation is different. Therefore, it's best to chose the method that makes the individual feel comfortable with.