Universal Shipping Cost Estimator Overlay

WHAT IT DOES

This script automatically detects shipping cost information on any product page and gives you a clear, instant summary of what you'll actually pay. It extracts shipping rates, identifies free shipping offers, captures estimated delivery times, and calculates a complete total that includes product price, shipping, and tax. The results appear in a floating badge that shows your total cost at a glance, with optional breakdown of product price, shipping, and tax amounts. No more hunting through shipping policies or adding up numbers manually—the script does it for you instantly.

WHERE IT RUNS

The script works on any product page across the web—Amazon, eBay, Walmart, Best Buy, Etsy, Shopify stores, and thousands of other e-commerce sites. It runs on any page that displays a product price and shipping information, regardless of where that information is located. The script's multi-layer detection finds prices in price elements, JSON-LD data, or text content, and finds shipping info in dedicated shipping sections, product descriptions, or shipping calculators.

HOW TO USE

After installation, the script scans automatically when you load a product page. Open the panel to customize your experience: set your country and postal code for accurate estimates, adjust the tax rate for your location, choose whether tax is included in the total, and toggle the breakdown display. Move the shipping estimate badge to any corner of your screen using the position selector. Click "Estimate Now" to re-run the calculation after dynamic content loads. Click the badge itself to toggle its opacity for a less distracting view. All settings are saved and persist across pages.

TECHNICAL MECHANISM

This script uses a multi-stage extraction pipeline to assemble a complete cost estimate. First, it locates the product price using a prioritized selector strategy that checks common price elements (data-price attributes, .price, .product-price, schema.org itemprop, and e-commerce specific selectors), then falls back to regex-based price detection in visible text. Second, it identifies shipping information using a similar selector strategy combined with keyword scanning for terms like "shipping," "delivery," and "postage." It extracts flat rates, detects free shipping indicators, and parses estimated delivery day ranges. Third, it applies configurable tax calculation based on the user's local tax rate. Finally, it presents all data in a persistent overlay badge that updates as page content changes. The entire pipeline uses DOM mutation observation to re-calculate when dynamic content loads.

THE PANEL

The settings panel is fully draggable and can be positioned anywhere on your screen. It automatically snaps to the nearest edge when released, keeping your workspace organized. The panel can be collapsed to a small bubble showing only a gear icon, and restored with a single click. Its position is remembered across page reloads using GM_setValue. The panel also responds to the Escape key, which instantly hides it until you click the bubble again. All settings are saved immediately when changed and persist across browser sessions.

PLEASE NOTE

This script requires the free BotGentz extension to run. Shipping costs and tax rates vary by region and may change over time. Always verify shipping costs at checkout before completing a purchase. The script's estimates are based on visible page data and may not reflect personalized offers, membership discounts, or real-time shipping rates. The script does not access, store, or transmit any personal data, purchase information, or browsing history. All extraction and calculation happens locally in your browser, and no information ever leaves your device.