Collectors want accurate pricing data and the best basketball card pricing guide is simply to search eBay for completed sales. These numbers are not what sellers are putting on their price tags, or prices that are a few weeks or a month old in a printed price guide but rather these are the actual numbers that collectors are buying the cards at right now.
The most current pricing data is important for when prices change quickly. A championship, trade, improvement in play or an award can get collectors interested in a current NBA player's cards. An injury, trade, benching or off the court controversy could send a player's prices down in a hurry.
Retired players can also have cards that change in value. Auction results often dictate future prices and all it takes for prices to soar are two bidders who are after the same card, whether for their registered sets or simply a collection. A new collector looking for MINT 10 cards could send prices up, by creating bidding wars, while a store or collector breaking up several sets could mean a bigger supply and some possible bargain prices.
The completed search can be sorted in several ways, like highest price first, but a more useful option to detect a trend in pricing is to sort by the "End Date: recent first". When using the completed search, also see how many results are in red compared to green. The red prices are cards that did not sell. If the page is full of green completed prices it can indicate a popular player. A card that collectors want is the Kyrie Irving 2012-13 NBA Hoops Kobe's All-Rookie insert. Not long after issue, the card listings were not only all green, they had maintained a consistent value for several months.
When searching for rare cards of lesser-known players, the eBay completed sales can indicate when it is time to buy or sell. There are few collectors looking for an Arnie Risen card from 1948 Bowman, and completed sales results can indicate when these collectors have found their cards. This could mean prices decrease, with little demand for the supply available. Typically, eBay completed sales show that there are buyers for his cards when they do appear.
What collectors will get from studying the eBay completed sales is an accurate idea of the market—a sort of living basketball cards pricing guide. Sellers will have an idea of what prices they could get for their cards while buyers might look at the completed sales and stay under that price with their bids to try to get a bargain.