Ahsan Allahu ilaykum. Sometimes I sell my own items on a secondhand platform like Facebook marketplace. I take clear pictures and mention any flaws, and I set a price I estimate is fair. Is there anything I need to know concerning a transaction like this? Jazak Allahu khayr

Ustadh AbdulAziz al-Haqqan

No, this is allowed as long as the description is clear and accurate, as well as the pictures or videos you provide. If the person wants to see them (or if they come to see them in person), then that would be even better.