1. Costing nothing
   - complimentary, free, gratis, gratuitous

See also: unpaid

• policeman bird
• policewoman
• policy
• policy change
• policy maker
• policy-making
• policyholder
• polio
• poliomyelitis
• Polioptila
• poliosis
• poliovirus
• poliovirus vaccine
• polis
• polish
• Polish monetary unit
• Polish notation
• polish off
• polish up
• polished
• polished rice
• polisher
• polishing
• Polistes
• Polistes annularis