Inside Lookout: How ListPrelo Finds Deals While You Sleep

Every reseller knows the feeling: someone else got there first. The underpriced MacBook, the estate-sale KitchenAid, the garage-sale Xbox — deals don't wait for you to remember to check.

That's why we built Lookout: a deal scanner that watches eBay and Facebook Marketplace around the clock and pings you when a listing crosses your profit threshold — not a price threshold. This post walks through exactly how it works, with real screenshots from a real hunt.

Tell it what you flip

Open Lookout from the ListPrelo sidebar and you get one question: what are you hunting?

Type the item you know how to sell. Pick where to hunt — eBay ships nationwide, Facebook Marketplace is your local pickup radius. Then set the only number that matters: your bar.

Here's the part that makes Lookout different: the bar is profit after fees, not price. You can say "alert me at ≥ $30 estimated profit" or "≥ 40% margin." Under the hood, every candidate listing gets scored:

est. profit = real sold comps − marketplace fees − shipping − asking price

And the comps are computed against each listing's own model — a 2019 13-inch MacBook Pro is compared to what 2019 13-inch MacBook Pros actually sold for, not to some blended average that a $2,500 M3 Max drags upward. A cheap listing isn't a deal unless its own market says so.

What comes back

Within a minute of creating the watch, the first scan lands:

Every hit shows its receipts: asking price, the sold-comps value for that exact model, estimated fees, and the profit that's left. The list is ranked best-first — the top hit here is a $70 MacBook Pro 13" against ~$200 of sold comps: +$91 after fees, a 46% margin.

Notice the line above the hits — that's the scan funnel:

50 listings seen → 49 matched your query → 14 comped · 5 had no margin at market price · 1 lacked enough sold data → 8 deals

Lookout shows its work on every scan. When a watch comes back quiet, you can see why it's quiet — the market had no money in it, and there's even a link to the same raw eBay and Facebook searches it scanned so you can judge for yourself. A deal scanner you can't audit is a deal scanner you can't trust.

From alert to owned to listed

Expand any hit and Details pulls the full listing — seller's description, condition, all the photos — so you can judge it without leaving the page. Like what you see? Open the listing and buy it.

Then tap Bought it, and the sourcing loop closes: ListPrelo instantly creates a draft listing carrying the item's photos, the seller's description, a price pre-set to the comps median — and the money trail handles itself. What you paid becomes the item's cost basis and a COGS expense, automatically. When the item sells, your profit numbers are true without a spreadsheet.

When you don't know what to hunt

Watches are for items you already flip. The Arbitrage Explorer answers the harder question: what should I be flipping?

Pick a category and the Explorer maps where the money is: each item identity's real sold median, its sell-through velocity (a fat margin on something that sells twice a year is a storage unit, not a flip), the cheapest live listing right now, and an arbitrage score that combines them. One click turns any row into a standing watch — or sweeps your area for the top local deals in that category, right now.

Why this beats price trackers

Price alert tools tell you when something is listed under $X. But a $30 iPhone isn't a deal just because iPhones "average" $250 — if it's an iPhone 6, its own market says $35, and there's nothing there. We learned that the hard way while building this, and it's why every number in Lookout traces back to real sold data for the specific item in front of you.

Lookout is live now for ListPrelo users — the free plan includes one watch, and Pro unlocks as many watches as you need, the Arbitrage Explorer, and area sweeps. Set your first watch tonight; the radar hunts while you sleep, and the next underpriced MacBook pings your phone instead of someone else's feed.