@ Mods & Community,
I vote for both:
1. Escrow must be accepted by all sellers, however they have the option to additionally not use escrow when selling as long as they offer it.
2. All sellers must post an asking price in their selling threads
All seller threads not offering escrow or listing an asking price would be locked immediately. This is similar to how it works on reddit r/hardwareswap and works very well (they mostly use paypal instead of escrow though)