Where I live there are only two boxing gyms, kinda sad for a city of 300,000-400,000. At one it costs about $50/month, at the other there is a drop-in fee of about $12-$15, but its been a while so I don't remember exactly how much it was. If you're looking to avoid submission holds etc. you might want to consider MMA, because a boxing coach isn't going to teach you much about submissions.