Like your recent other unanswered question, and in other aspects of the game, the answers are subjective.

Not every player gets the same offers, and if and where they do, and the players acounts are indentical, their response to offers may not be.

Some subscriptions are more "worth it" than others imo. Of course, I only do the subscriptions that benefit me the most so...... that criteria will be different for each person. Some are charged for a week, others for a month. Can find specials and deals that last longer i.e. 90 days (longest I've seen)

What are your needs? How BAD do you need them? How much are you willing to pay? These are all things only you can answer.