How can I tell if a Lab puppy listing is a scam?

Short answer

The FTC says scam ads often offer purebred puppies for a few hundred dollars, push you to pay upfront, then add shipping or vet fees, and ask for gift cards, wire transfers, payment apps or crypto. Reverse-search the photos, search the seller with 'scam', insist on a visit or live video call, and pay by credit card.