How the Nu Stack Chrome Extension Finds Deals While You Browse

Browsing online marketplaces for gold and silver deals is a time sink. You scroll through hundreds of listings on Facebook Marketplace, most of which are overpriced, mislabeled, or not actually precious metals at all. Occasionally you spot something promising, open a calculator, look up spot price, estimate the weight and karat from the listing title, and try to figure out if it's worth pursuing. By the time you've done the math, someone else has already messaged the seller.

The Treasure Hunter Chrome Extension was built to fix this. It scans marketplace listings as you browse and overlays deal quality badges directly on the listings — so you can see at a glance which deals are worth your time and which ones to skip.

How It Works

Treasure Hunter is a Chrome browser extension that runs in the background while you browse supported marketplace sites. When it detects a precious metals listing, it reads the listing title, parses it for karat, weight, and purity information, calculates the melt value using cached spot prices, compares that melt value to the asking price, and overlays a color-coded badge on the listing showing the deal quality.

You don't search within the extension. You browse marketplaces the way you normally would — scrolling through listings, searching for keywords — and the extension annotates what you're already looking at. It works with the page, not as a separate tool.

The extension uses cached spot prices that refresh every five minutes, so the melt value calculations are based on near-current market data without hammering price APIs on every page load.

Supported Marketplaces

Treasure Hunter currently scans five platforms:

Facebook Marketplace — the largest source of secondhand gold and silver listings for most buyers. The extension scans listing tiles as you scroll the marketplace feed and on individual listing detail pages. It also handles Facebook's infinite scroll — as new listings load, they get scanned automatically.

Facebook Groups — precious metals buy/sell/trade groups are active communities where deals move fast. The extension scans group post feeds for gold and silver listings and overlays badges just like it does on Marketplace.

eBay — scans listing pages for gold and silver items. eBay has higher volumes and more competitive pricing, so the extension helps you quickly filter which listings are priced below melt value.

Craigslist — scans listing rows in the jewelry and metals categories. Craigslist deals tend to be local, which means you can inspect before buying — the extension helps you decide which listings are worth driving to.

Whatnot — scans live auction and listing cards. Whatnot's precious metals auctions move fast, so seeing a deal quality badge before bidding is valuable.

The Scoring System

Treasure Hunter parses listing titles for keywords that indicate karat (10K, 14K, 18K, 585, 750, etc.), weight (grams, oz, dwt), and purity (sterling, .999, .925). When it finds enough information to estimate melt value, it compares that to the listed price and assigns one of three deal quality tiers:

Strong — the asking price is significantly below estimated melt value. These are the listings you want to pursue immediately. Strong deals don't last long, especially on Facebook.

Good — the asking price is below melt value with reasonable margin. Worth investigating, especially if the listing has photos that suggest the weight or karat might be better than what the title indicates.

Moderate — the asking price is near melt value. Margin is thin. May still be worth pursuing if you think the seller will negotiate, or if the piece has numismatic or collector value above melt.

Listings that the extension can't parse — no karat mentioned, no weight, vague descriptions like "gold jewelry lot" — don't get a badge. You'll need to evaluate those manually.

What It Looks Like

When you're scrolling Facebook Marketplace and a listing says "14K gold chain 22 grams $400," the extension calculates the approximate melt value for 22 grams of 14K gold at current spot, compares it to the $400 asking price, and overlays a badge directly on that listing tile. You see the deal quality without opening the listing, without pulling out a calculator, and without checking spot price.

On listing detail pages, the extension provides more information — the estimated melt value and the breakdown of what it parsed from the title.

The badges are visually distinct and designed to be readable at a glance as you scroll. You don't have to hover or click to see the tier — it's right there on the listing.

The Practical Impact

Without the extension, evaluating a single marketplace listing takes 30–60 seconds of mental effort — read the title, estimate the karat and weight, check spot price, run the math, decide if it's worth pursuing. Multiply that by the dozens or hundreds of listings you see in a browsing session, and you're spending significant time on deals that aren't worth pursuing.

With the extension, the math is done for you on every parseable listing. You scan the page, your eyes go to the badges, and you click only on the listings that are already flagged as good or strong deals. A thirty-minute browsing session becomes dramatically more efficient because you're spending your time on leads, not arithmetic.

For buyers who source a significant portion of their deals online — and in 2026, that's a growing number — the extension turns marketplace browsing from a needle-in-a-haystack exercise into targeted deal hunting.

Getting Treasure Hunter

The Chrome Extension requires a Nu Stack Pro plan ($9.99/mo). You can install it from the Tools section inside the Nu Stack app. Stacker tier users will see an upgrade prompt — the extension is Pro-only because it relies on infrastructure that supports the advanced scanning and scoring features.

Once installed, log in with your Nu Stack account, and it activates automatically on supported sites. There are no settings to configure — it starts scanning as soon as you visit a supported marketplace.

If you're already using Nu Stack for your calculator, inventory, and profit tracking, the extension connects to the same account. Deals you find through the extension can be evaluated in the Calculator and logged into your Inventory, keeping your full buying workflow in one system.