A LEGO set price checker for Facebook Marketplace and Kijiji

How to price-check a LEGO set by hand

Every LEGO set has a number, printed on the box and on the cover of the instruction booklet. That number is the key to its price.

1. Find the set number. It’s often in the title of LEGO for sale listings. If it isn’t, look for it on the box in the photos, or ask the seller.
2. Open the set on BrickLink and choose Price Guide.
3. Read the used “last 6 months sales” box. That is what buyers actually paid. The “current items for sale” boxes are asking prices, which run high.
4. Adjust for condition. Missing minifigures cut the value most on many themes; a missing box or booklet less.
5. Check the currency. BrickLink’s help says the guide shows your local currency by default. Make sure it reads CA$ or US$ before you compare.

The used LEGO price guide walks through each step with a worked example. It takes a few minutes per listing, which is fine for one set and slow for a page of them.

How Sift reads the set number

Sift recognises a LEGO listing from the word LEGO in the title, or from words only LEGO uses: DUPLO, Technic, Ninjago, Bionicle, Mindstorms, BrickHeadz, minifig. It leaves out LEGO tables, storage, clothing, decor, video games, light kits and Legoland tickets, and Mega Bloks, Playmobil or K’nex listings that never mention LEGO.

Then it looks for the set number: 4 to 7 digits after “set”, “#”, “no.” or the word LEGO, or a lone 5-digit number in a LEGO title. A price, a piece count or a year is never mistaken for one, and a knock-off’s own number (“Lepin 05132”) is ignored. The details card opens with LEGO · set 75192, so you know which set you’re pricing before you read a word of the description.

BrickLink’s price guide, one click from the listing

With a set number found, the first link under Check elsewhere is BrickLink price guide, which opens the price guide tab for that exact set. Without a number, the link is Search BrickLink, a search on the listing’s title with the noise trimmed off. After it come the links every listing gets: Sold on eBay, Search by image and Google Shopping, and for Canadian searches, the same search on the other site.

The links are plain links. Sift opens them only when you click, and makes no requests to BrickLink on its own. The prices themselves live on BrickLink; Sift doesn’t copy or convert them.

Is it LEGO brand?

A lot of secondhand “LEGO” is another brick brand. Sellers often say so, just not in the title. Sift reads the whole listing and marks May not be LEGO brand (on the photo, Maybe not LEGO) when it finds wording like:

• “compatible with LEGO”, “LEGO compatible”, “building blocks compatible with all major brands”
• “not real LEGO”, “off-brand”, “knock-off”, “LEGO-style”, “clone bricks”
• a clone brand by name: Lepin, Lele, Mould King, Decool, Xingbao, BlueBrixx, Reobrix, Sluban, Banbao, Wange, Pantasy, Funwhole, Gobricks, Qman, Keeppley, Sembo or Mega Bloks
• the French versions, such as “compatible LEGO”, “pas des vrais LEGO” or “imitation”

Point at the chip and it shows the words that triggered it. A mixed bin that says “Mega Bloks removed” stays clear, because the seller already took them out.

Sift reads words, not plastic. A seller who calls a copy LEGO and never hints otherwise won’t trigger the chip. For the in-person checks (the logo on the studs, the box print, the minifigure neck), read how to spot fake LEGO, and for figures, the minifigure guide.

Missing pieces, minifigures and the good signs

Completeness moves a used set’s price more than anything else, and sellers bury it in the description. Sift marks it on the photo:

• Incomplete set: “incomplete”, “missing pieces”, “not complete”, “about 95% complete”, “not sure if it’s complete”, “pièces manquantes”.
• No minifigures: “no minifigs”, “minifigures not included”, “without the figures”, “minifigs sold separately”.

Green chips mark the listings worth opening first: Complete set, Minifigs included, Sealed (“factory sealed”, “NISB”, “new in box”, “never opened”) and Instructions included. The reading handles negation and hedging: “no missing pieces” counts as complete, “complete?” doesn’t, “sealed bags” isn’t a sealed box, and “instructions online” isn’t instructions included.

Price drops, fair price and alerts

LEGO listings get everything else Sift does. It remembers each price it sees, so a set that drops from CA$180 to CA$150 shows the drop on the photo, with the dated history when you point at it. The fair-price label (Below typical, Typical, Above typical) compares a listing with the rest of the page, which works well on a search for one set number and means little on a broad search for “lego”.

Save a set-number search and choose Watch this search. Sift checks it in the background as often as every 15 minutes and notifies you about new listings that pass your filters, up to 10 searches at once. Retired sets at a fair price go fast; an alert gets you there first.

Set it up in a minute

1. Open Sift’s settings, then Presets, and pick the one-click LEGO setup in Settings › Presets.
2. That’s the setup. It saves a preset called LEGO, applies it, switches the LEGO checks on and hides broken and for-parts lots. It never overwrites a preset you already named LEGO.
3. Search a set number on Marketplace or Kijiji, and open any listing’s details for the BrickLink link.
4. Watch the search if you want to hear about new copies.

The welcome page offers the same choice when you first set Sift up. Each category check also has its own switch on the Feed page of the settings, if you ever want LEGO listings left plain.

What Sift doesn’t do

Sift doesn’t authenticate LEGO, check bricks in photos or count pieces. It reads what the seller wrote and links you to BrickLink, where the prices are. A chip is a reason to ask a question, not a verdict. For buying in person, read buying used LEGO on Marketplace; for mixed bins sold by weight, read buying bulk LEGO.

Sift runs in Chrome, Edge and Brave on a computer. It doesn’t run in the Facebook app or on a phone. It needs no account and keeps everything on your own computer.

LEGO® is a trademark of the LEGO Group of companies, which does not sponsor, authorize or endorse this site. Sift is not affiliated with BrickLink or any brand on this page.