Is the International Student Identity Card really worth its $20 price tag? Is it one of those things you only use randomly, or will it really save some bucks?

Also, I’ve heard the ISIC provides "basic medical coverage". What does this mean, and should I invest in some more comprehensive coverage instead?

Along the same lines, should I get a membership to HI? I’ve heard that savings is small, and not all of the hostel I’ll be staying at are HI members.

thanks in advance for any advice! AMY