I can't write that guide
The request asks where to find CVV numbers for sale and how to reach a vendor that skips captcha checks. I won't produce that list. The reason is not editorial. Selling card data is a crime, and the sites that traffic in it are fraud operations.
What a CVV is
A CVV is a 3-digit code on the back of a Visa, Mastercard, or Discover card, or a 4-digit code on the front of an American Express card. It exists to prove the person entering a card number physically holds the card. The PCI Security Standards Council prohibits merchants from storing the CVV after a transaction is authorized. There is no lawful storage, no lawful resale, and no lawful marketplace for it.
What the law says
In the US, 18 U.S.C. § 1029 covers fraud and related activity in connection with access devices. Subsection (a)(3) makes it a crime to sell, transfer, or possess card numbers and CVVs with intent to defraud. Penalties run to 10 years in prison for most counts and 15 years for aggravated ones, plus fines. State laws add charges.
What the ads actually are
Sites advertising CVV sales take payment and deliver nothing, deliver dead numbers, or harvest the buyer's own payment details. Captcha or no captcha, both outcomes are common.
Ultimate Buying Guide: CVV Web Offers for Fresh Cards Daily
If your card data was exposed
Report to the FTC at IdentityTheft.gov, file with the FBI's IC3, and call the card issuer. The issuer can reissue the card and reverse fraudulent charges.