I'm selling an item on Letgo and someone interested in my product said he would send me a cashiers check for more than the value needed. then send a shipper to pick it up. Read on the internet that this is a common fraud.
Yes it is a big one with Craigslist...here is more to read https://www.craigslist.org/about/scams
And here is a link to the FTC about Fake checks.https://www.ftc.gov/search/site/fake%20check