Trusted prices for the TCG market.

To figure out what a card is really worth today, you have to hop between marketplaces and compare listings one by one — with bait listings and outliers mixed in, it's hard to tell which price is the real market rate.

GCI aggregates real sale data from multiple marketplaces, removes outliers, and presents it as a single estimated market price (low / median / high) with a price trend chart for each card.

On top of that, we condense the entire market into one index (GCI), so you can also see whether the market as a whole is heating up or cooling down.

GCI turns raw listings into market data through a 4-stage pipeline.

1. 1

   Collection

   We collect transaction data from multiple secondary markets, referencing both active and sold listings, prioritizing actual completed transactions.

2. 2

   Filtering

   Lot sales, suspected counterfeits, and unknown-condition listings are automatically excluded. Graded cards (PSA etc.) are tracked separately by condition. IQR outlier detection then removes anomalies that distort the market.

3. 3

   Price & Index Calculation

   From the cleaned data we derive each card's estimated market price (low / median / high) and price history. A TrustScore-weighted average (source reliability, listing type, condition) also feeds the market index with base value 1000.

4. 4

   Confidence Scoring

   HIGH / MED / LOW confidence is derived from sample count and outlier ratio, published alongside the data. Values with insufficient data are hidden or marked as reference values.