Agree with Mikhail. Self-development in Toastmasters is by doing - just like in a gym membership. Put in the hours and the effort. There is nothing to be learned by just listening because there aren't really lectures. It's mostly the evaluation of others of your speaking that becomes the learning portion. Of course the journey of speech writing, preparation and delivery hones your skills.
If you feel it's expensive, you can be aggressive in your development by seeking more opportunities to speak, and you can do this by club-hopping when you become a member. Just inform the club you wish to club-hop and clubs are generally receptive to this idea.