Use EBay. That is an accurate representation of the market. Search for what you have interest in, filter to sold items, and sort by most recent date. This will tell you exactly why the same retail products are on the Target/Walgreens/Walmart shelves Month to month, and stock of others cannot be found. These are scooped up and sold on the secondary market.Is there a reliable source that has what the retail price for boxes of cards should be? I know older sealed wax can go dor more and the market dictates that price but I can’t find anywhere what the price is for different box types of 2021 Topps or what the retail price originally was on older boxes.
A good example is the 2020 topps update release. When boxes first came out, hobby boxes were $130 and jumbos were $240. Since it wasn’t a strong release, after a month you could find hobbies under $90 and jumbo’s under $140. Unfortunately you won’t find blasters or hangers less than the MSRP.