Dual-pricing and cash-discount programs let merchants display a 'cash price' and a 'card price' (or apply a discount for cash payers) so the customer effectively pays the processing fee. The merchant receives the full ticket amount net of fees. Processors who operate compliant programs charge a monthly platform fee — usually $20–$50 — to cover the POS configuration, signage compliance, and Visa/Mastercard reporting needed to keep the program legal.
Done correctly, this is the highest-leverage cost-savings move available to a typical SMB: 100% of credit card processing cost goes away. Done incorrectly (improper signage, no disclosure, charging on debit) it's a fast track to Visa/Mastercard fines or account termination. The platform fee is the price of compliance.