Sold listings are the gold standard of market value — they reflect actual transactions, not asking prices. We pull from eBay's Finding API for individual sales and from TCGGOPRO for grade-aggregated medians.
Finding API is rate-limited at ~5000 calls / day across all users. When we hit the limit, the Sold tab falls back to our own cache (every successful Finding call writes to CardPrice). If both Finding and the cache are empty, you'll see the graded median summary from TCGGOPRO instead of an empty state.
Sample size matters: a $4,200 PSA 9 median with sample size 12 is more trustworthy than one with sample size 2. We display the sample count next to every median.