Bin stores are where people buy a semi truck load of Amazon returns. Dump all the stuff and large bins and sell the items for a fixed price per item. The owner just dumps all the stuff in these bins and you dig through it. No returns and opening items are under strict supervision so you don't loose parts. Most stuff is in clear plastic bags so you can get a look. Pricing starts at $6 per item on Thursday and drops $1 per day until Tuesday where all items are $1. Then on Wednesday they fill the bins back up.
Just Google "Amazon Bin Stores near me" and it will pull them up.
Here is an example.