No. You will not be hit, but you will be punching, just like a boxer does when training for a fight.
Yes, that is the basis of the training.
No, boxing cardio works your entire body and are as intense as you want them to be.
You will need: make a downpayment, gloves, handwrap/gloves, standard workout clothes, tennis shoes, and a ready-to-work attitude.
You can purchase a set of gloves from $30-$50 at a local sporting goods store such as Dick's or Sports Authority.
Sessions last one hour.
No gym membership is required.