All true. Though plenty of times I have seen lots of records similarly priced in different dealers boxes. That's why the often common discrepancies are difficult to fathom.
True about bartering. Only you'd better be clued up and make sure you handle said bartering in the right manner, or you'll be sent away with a flee in your ear and tagged as a chancer.
Saw a Della Reese - Clock we no hands - Rob Messer list £65. About right I thought, but just before payday, couldn't act. Then I was out next weekend and someone's got it in their box - £80. Offered £70 thinking if it's not accepted, I ain't buying it. Fortunately he accepted.
Closing comment spot on.