[jijojv]

I always use a virtual credit card number (like Citi provides) everywhere which has a daily hard limit.

[papichulo4]

Good advice indeed, but paying is only one part of the problem; you'd still owe the bill.

[Havoc]

Provides precisely zero protection against this.

Even if your card declines or you used a prepaid card...you're still legally liable for the full amount.