I wanted to buy something second-hand. Unfortunately, Facebook Marketplace is the shit where I live. So I thought I could quickly register, contact the seller, and delete my account afterwards.
However, I refuse to participate in this insanity. Video selfie my ass, Facebook.
Sadly it does seem to be very popular but I am sure there are some niche forums specific for certain items like tech related ones which also has a marketplace for tech products, audiophile ones for audio gear etc. I joined one to buy something and ended up being a part of the great community now so hopefully something works out for you as well.