You can not get a crack for glider, or IS for that matter, due to the fact that they check your information against their server's for subscription requirements. Of course, finding out what line does this, and redirecting it to a fake authorization file shouldn't be hard to do, but if your going to bot, then your going to want to be on top of things with updates and such, therefor, paying the subscription is more than worth it if you wish to keep your WoW account safe.
If you don't have a CC, then go to a gas station and ask if they offer pre-paid credit cards or something that acts as such. Many gas stations do, or if not, they know what your talking about and where to go to get one.
Cheers,
Windy.