I’m interested in finding out how the prices of several cards (mostly graded, but ungraded also correlates with graded, and booster boxes usually correlate as well) have changed over the last years, how should I go about finding it?
eBay only has a 3 month history and PWCC for example does show some information but not for too many cards and the prices are always higher than their eBay counterpart but I’m unsure how much the premium is compared to eBay… So pretty much, how do you guys go about it?