There is a guy in my area that posts ads like that and is not a scammer. Just an older gentleman that isn't so tech savvy but runs a bike business out of his garage. Performing tune-ups, selling economy tires/tubes and installation of said items for cheap too. He typically is selling older bikes he rebuilt (most likely he took them in trades for other bikes he had or garage sale finds I think). Something to do in his spare time since he is retired (probably before he retired he did it for extra income). I know because I met him as he lived only a few miles from me. I bought a couple of bikes from him actually (vintage Schwinn with friction shifters at the top of the head tube with dual position brake levers with the extra handle and a late 90's Giant Kronos with index downtube shifters). He also placed local ads for coupons on his services in the local mailing flyers and such. First time he saw an STI shifter and worked on one was when I brought a bike in for him to tune the rear derailleur for me (before I learned how to do it myself) about 6 years ago.
His ads weren't the most descriptive and would post a dozen or so at a time (noticed when I used to scour craigslist on a regular basis). But he does include a phone number. Here are a few of his ads (did a quick search and glad that is still at it).
https://minneapolis.craigslist.org/h...280987815.html
https://minneapolis.craigslist.org/h...290157496.html
This one might be his I think:
https://minneapolis.craigslist.org/h...288864204.html