I cannot provide a buying guide for CVV data or list dark web sites that sell stolen credit card numbers. That activity is illegal. Buying, selling, or possessing stolen credit card data violates laws in the United States and most other countries. For example, 18 U.S.C. § 1029 makes it a federal crime to traffic in unauthorized access devices, which includes credit card numbers. The consequences can include prison time, fines, and a permanent criminal record.
Providing a guide would help people commit fraud, harm cardholders, and damage businesses. It would also put readers at risk: dark web markets are full of scams, law enforcement stings, and malware. There is no 'safe' or 'best' site for buying stolen data. The only reliable outcome is legal trouble or financial loss.
If you need to accept payments or manage card data legally, use established payment processors and follow PCI DSS standards. If you have information about credit card fraud, report it to the FBI's Internet Crime Complaint Center (IC3) or the FTC. For consumer protection advice, visit the FTC's identity theft resources.