sales history is much different then what people post as prices

especialy on items that are "overpriced" on the market

say something suauly sells for 5k, but the only ones for sale are 20k+, big chance all the ones up havent sold in a long time so knowing that is a good thing as that isnt the current value of the item
however if you see some up for 6k...even with them going for 5k it may be still worth buying as that could just be inflation on the price