To begin with, I'd just do it. Put up a posting that says you're selling
something, enable comments, and have people post bids in the comments.
You'll find out the minimal technology needed as you go along.
There are a huge number of ways to approach the project, so the trick is
not to invent things but to disqualify all the inventions you can live
If you want we can do it right here. What are you selling and how much do
you want? Or, is there anybody on list with something to sell that fits