The calculation is advance amount × 1.30.
$10,000 advanced becomes $13,000 repaid.
$25,000 advanced becomes $32,500 repaid.
$50,000 advanced becomes $65,000 repaid.
$100,000 advanced becomes $130,000 repaid.
The difference between the amount received and the total payback is the factor cost. Separate origination, underwriting, ACH, or broker fees can increase the real cost further.