TCGPlayer Web Price Guide Overlay

WHAT IT DOES

This tool visualizes TCGPlayer price guide data for trading cards and collectibles. It scans product pages for market price, listed median, low price, high price, and best listing price. The panel displays a summary showing all key price metrics with color coding—best price in blue, high prices in green, and low prices in red. A price history chart shows recent price trends with color-coded bars—green for above-market prices, red for below-market, and gray for flat. Trend direction is shown with percentage change, and volatility is calculated as the standard deviation of prices. Quick "View Listings" and "Set Price Alert" buttons provide easy access to active listings and price monitoring.

WHERE IT RUNS

The script activates on TCGPlayer pages (tcgplayer.com), including product pages, price guide views, and card detail pages. It automatically detects price guide data using multiple extraction strategies that work across different TCGPlayer layouts. The panel appears as a draggable overlay that stays accessible as you browse card prices.

HOW TO USE

Navigate to any TCGPlayer product or card page. The panel will appear showing the price guide summary with market price, median, low, high, and best listing. Toggle "Chart on/off" to show or hide the price history chart. Set the "Refresh (s)" input to control how often the script checks for updates (default 60 seconds). The "Refresh" button manually updates the data. Click "View Listings" to open the active listings page in a new tab. Click "Set Price Alert" to configure a price alert notification—the script will notify you when the price changes significantly. The trend indicator shows whether prices are moving up or down with percentage change, and volatility shows price stability.

THE TECHNICAL MECHANISM

The script employs a multi-strategy DOM extraction approach for TCGPlayer's price guide interface. It first attempts structured selectors targeting known class names like .price-guide, .price-stats, and .market-price, then falls back to heuristic text scanning using regex patterns for "market price", "listed median", "low price", "high price", and "best listing". Prices are extracted using regex for currency amounts with support for $, €, and £. Price history is extracted from price history elements or by collecting all currency amounts from the page. The trend direction is calculated by comparing the first and last prices in the history. Price volatility is calculated as the standard deviation of the price history. The best listing is identified as the lowest available price. The chart uses CSS for rendering with bar height proportional to price relative to the range. The auto-refresh uses setInterval with a user-configurable interval, and a MutationObserver watches for page updates. All settings are persisted using GM_setValue.

THE PANEL

The panel is fully draggable by its header and remembers its position on the page across sessions. It can be collapsed to a small bubble using the minimize button, then restored by clicking the bubble. The panel resizes automatically to fit its content and can be closed with the Escape key or by clicking the close button. The panel's position and state persist globally, so it returns to the same location on subsequent visits.

PLEASE NOTE

Requires the free BotGentz extension to run. TCGPlayer may update its site structure, which could affect the script's ability to detect price guide data — updates will be released as needed. All price data is read from the page and displayed locally; nothing is transmitted externally. The script reads data from the visible page and does not access any data beyond what is visibly presented. The script does not modify your TCGPlayer account or listings. The price history chart uses data from the visible page and may not reflect the full price history. Volatility is calculated based on available data and is for informational purposes only. The "Set Price Alert" button creates a local notification only—it does not create a TCGPlayer price alert. This tool is for informational purposes only and is not affiliated with TCGPlayer.