Every deal has a tell.
Screenshot any Marketplace listing and send it to DealTell. It finds the exact model, checks what it really sells for, spots the catch, and tells you what to offer — and when to walk away.
Runs inside the ChatGPT or Claude account you already have (free accounts work). You're not buying a prompt — you're buying the research method that makes it check like a skeptic.
Video embed goes here
Same listing. Different decision.
Pick a listing. See what your gut says, then what DealTell says.
Top of the line when I bought it, paid way more than this. Works great, just don't use it anymore.
What it actually is
Looks like the LG 34UC98-W, a $1,199 flagship in 2016. 34" 3440×1440 curved IPS, Thunderbolt 2. A great screen in its day.
The catch
"Paid way more" was ten years ago. Right now LG sells a brand-new 34" ultrawide with a 120Hz refresh rate for $199, with a warranty. That's a dollar less than this used one. The old price tag is doing the selling here.
Check before paying
Confirm the model label on the back, test every input you'll use, and look for dead pixels and backlight bleed on a dark screen.
Your message to the seller
Hi! Is this still available? Would you take $130 cash? I can pick it up this evening.
Bottom line: Still a nice monitor, but not at $200. Offer $130 and walk above $160.
Runs and drives great. Cold AC. Priced to sell, need it gone this week.
The catch
This model's CVT transmission is a well-known weak point at this mileage. A replacement runs $4,000–$7,000 at an independent shop, which could be more than you're paying for the whole SUV. The low price may be the market pricing in that risk.
Ask the seller first
Has the CVT ever been replaced or serviced? Any warning lights? Can you send the VIN?
Bottom line: Don't call this a deal yet. Get the CVT history and VIN, then have a mechanic inspect it before any money changes hands.
Works perfect, just upgraded. Comes with power cord.
What it actually is
Likely the Samsung U28E570D: 4K, 60Hz, but an older TN panel, not IPS. Colors and viewing angles are weaker than modern 4K screens.
Check before paying
Confirm the model label on the back, look for dead pixels on a solid white screen, and test the 4K input you'll actually use.
Bottom line: A good buy for work and everyday use at $80, just not the premium screen it sounds like. Don't risk losing it over $5.
Examples from real checks. Prices change, so DealTell researches fresh every time.
Marketplace prices are mostly guesses.
One bad buy costs more than DealTell ever will.
Sellers price from what it cost years ago.
An old sticker price makes an average item look like a bargain.
The exact model changes everything.
"4K Samsung" could be worth $60 or $300. The listing rarely tells you which.
"Like new" is a claim, not a test.
Known defects, locked phones, and tired transmissions don't show up in photos.
Sometimes new is cheaper.
A retail sale can beat a "sealed" Marketplace price — and it comes with a return policy.
"Someone else is coming at 5" is a sales tactic.
Pressure is how people skip the checks. DealTell hands you the checklist before you drive over.
Five minutes to set up. Every listing after that.
No app to install. If you can copy and paste, you can set this up.
Create your DealTell project
Make a new project in ChatGPT or Claude and name it DealTell.
Paste and upload
Paste in the instructions and upload the DealTell research file. The setup video walks you through it.
Send any listing
Drop in a screenshot or paste the listing text and say "DealTell this listing."
Then just keep asking.
Every verdict is a conversation. Here's what people ask next.
You could just ask ChatGPT. Here's the difference.
ChatGPT answers the question you ask. DealTell asks the ones you didn't know to.
Built and tested over weeks of real Marketplace buys, so you don't have to spend those weeks learning what to ask.
Skip one bad $200 buy and DealTell has paid for itself four times over.
Listed at $700. Bought for $525.
I built DealTell for my own Marketplace buys. This week it checked two ASUS ProArt 27" 4K monitors listed at $350 each, found the pair sells new for about $660 with a warranty, and wrote the offer you see here. The seller said yes in under 90 minutes.
$175 saved on one purchase. DealTell costs $47.
— Jay Sherman, creator of DealTell
What you get
The DealTell advisor
The full research method, pricing checks, and negotiation playbook, set up inside your ChatGPT or Claude. It checks like a skeptic and helps you buy at your price.
Three short videos
What DealTell does, how to set it up, and a real listing taken from screenshot to decision. About 15 minutes total.
Step-by-step setup guide
Screenshots of every step, plus tips for getting the most from a free account.
Flip Mode
For resellers: real profit after fees, how fast it'll sell, and your max buy price.
Buying to resell? Know your profit before you pick it up.
- Resale value from sold prices, not wishful asking prices
- Net profit after fees, shipping, and repairs
- How fast it's likely to sell
- Phone traps like carrier locks, blacklisted IMEIs, and iCloud locks
Sample report: a used iPhone
Bottom line: Flip it if the IMEI is clean and it's carrier unlocked — check both before you drive over. At $220 you clear about $65. Don't go past $235.
Illustration only. Your real numbers come from live sold prices in your market.
If you've ever wondered “is this a good price?”
Get DealTell
- The DealTell advisor — research method, pricing checks, and negotiation playbook
- Three short videos
- Step-by-step setup guide — up and running in 5 minutes
- Flip Mode for resellers
- Use it on every listing, forever. No subscription.
🎉 Launch special: the first 20 buyers save $20 with code FIRST20
14-day money-back guarantee. If DealTell doesn't earn its keep, email us within 14 days for a full refund.
Works on free ChatGPT and Claude accounts. If you check listings every day, a paid A.I. plan gives you higher limits for screenshots and research.
Questions
Do I need a paid ChatGPT or Claude account?
No. DealTell works on a free ChatGPT or Claude account. Free accounts have daily limits on screenshot uploads and web research, so pasting the listing text instead of a screenshot helps. If you check listings every day or flip for profit, a paid plan will feel smoother.
Does it only work on Facebook Marketplace?
No. It works on any listing you can screenshot or copy, including Craigslist, OfferUp, and eBay.
Is this an app?
No. You're getting the same research method I use on my own Marketplace buys, set up inside your own ChatGPT or Claude account in about 5 minutes. Nothing to install, nothing to renew.
Does it work on my phone?
Yes. Setup is easiest on a computer. After that, use DealTell from the ChatGPT or Claude app while you shop.
Can I just send it the Marketplace link?
Marketplace listings usually sit behind a login, so links often won't open. A screenshot or the pasted listing text works better, and the setup guide shows you how.
Are the prices guaranteed?
No. DealTell researches current prices and known problems and gives you estimates with a confidence level. It can't see or touch the item, so always inspect and test before you pay.
Does it work with other AI tools?
DealTell is built for ChatGPT and Claude, which both let you save project instructions and files. Other AI apps aren't supported.
Is DealTell connected to Facebook, OpenAI, or Anthropic?
No. DealTell is an independent product. It isn't affiliated with or endorsed by Meta, Facebook, OpenAI, ChatGPT, Anthropic, or Claude.
What if it's not for me?
Email us within 14 days and we'll refund your $47. No hoops.
Before you buy, get the DealTell.
Know what it's worth, what to check, what to offer, and when to walk away. Every time.
Get DealTell $47