Haggle

Inspiration

Negotiating prices, especially in online market places like Kijiji, Facebook Marketplace, or even dealerships for car prices can be an absolute nightmare. Not just the negotiating part, but also how long it takes

If you need a plumber, you might spend 45 minutes on hold, explain yourself four times, and still end up paying too much because negotiating is awkward and stressful and nobody taught us how to do it.

What it does

Haggle calls businesses for you. You type in what you need, the Haggle Concierge finds the businesses, the Haggle Negotiator dials them up, asks all the annoying questions, and comes back with a neat little comparison table. Then if you want, you set a budget limit, hit go, and Haggle calls BACK to negotiate. You sit there and do nothing. It comes back with a better price. You win.

How we built it

ElevenLabs does the talking. Genuinely sounds like a person, businesses had no idea. Claude handles the brain work: generating call scripts, pulling structured info out of transcripts, writing summaries, and running negotiation logic. FastAPI runs the backend, Next.js handles the frontend, and Twilio connects everything to actual phone lines. We also threw in a scraper to find real business numbers so the whole thing works end to end.

Challenges we ran into

Turns out calling real businesses with an AI at a hackathon is a lot. Telephony setup alone almost ended us. We also had to make sure the agent never went rogue and promised something the user didn't approve, which was harder than expected. And getting ElevenLabs to sound natural mid-negotiation without weird pauses took way more tuning than we thought.

Accomplishments that we're proud of

It actually works. The AI negotiated, and got a better price. In two and a half hours. That still feels insane to us. Also the ElevenLabs voice is so good that one of us genuinely forgot for a second it wasn't a real person talking.

What we learned

Telephony is hard. LLM latency during live voice calls will humble you. And honestly, negotiation is a lot more structured than people think. Once you break it down into anchoring, countering, and knowing your walkaway point, it becomes a script. Which means an AI can run it. Which means we never have to haggle at a car dealership ever again.

What's next for Haggle

Calling three dealerships at the same time and pitting them against each other. Multi-call mode where Haggle runs parallel negotiations and takes the best offer. Also want to add voice cloning so it negotiates in your voice. Imagine sending yourself to go buy a car. That's the dream.