Craigslist is LOADED with scams, and especially now, with the pandemic in full swing and many people seeking a cuddly pet to keep them company. The people placing the ads often do not even have a dog, at all. They post ads, put cute pictures in the ads, and a great description. They may tell how they got the dog/puppy and then could not care for it due to work/health problems/too busy/allergies. They, ultimately, will ask for a deposit, or a shipping fee, even if the animal was first advertised for free or at low cost.
They often even live in a country totally different from where the ad has been posted, or have the same/similar ad posted in other cities.
Once you have given them your money, you will not hear from them, again. They may also be “fishing” for sensitive information from you in order to take advantage of you, or ask you to respond to a “code”.
If you plan on responding to an ad like this, do not give any personal information; do not respond to a CODE; do not give any money.
Unless and until you have a dog right there in front of you, consider this a scam ad and proceed with extreme caution. You might sometimes also notice the ads seem pieced together with odd details, or the person cannot communicate very well, or they sometimes add lots of odd characters in the ads (but not always), such as ** ## !!.
Again: Proceed with caution; no money or information unless you have a dog in front of you.
Consider contacting a rescue league or go to the site, “Petfinder”. This site represents shelters and rescue leagues. They have to be properly registered to be on the site.
By the way: A puppy of six weeks is too young to be adopted. It will not have had any vaccinations, and can easily die of Parvo because of that. It will not be properly socialized yet, either. It needs to be with the mother dog at least until 8 or 10 weeks.
Look up: Craigslist pet scams