You can blow over $2,000 on facebook ads without a single sale, except plenty clicks without any meaningful conversion (sale). Pay Per Click (PPC) is a dying breed - enter Pay Per Sale, where you're not charged for advertising until you make that sale, and just billed for each sale you make and not some useless mere clicks.

Pay-per-sale or PPS is an online advertisement pricing system where the publisher or website owner is paid on the basis of the number of sales that are directly generated by an advertisement