The LLM Thought a Dollar Was Still ₦450: Building a Car Pricing Engine for a Market With No Data

How I built an AI valuation engine for Nigerian used cars, and what it taught me about why you should never let a language model price anything on its own.

The problem: a market where nobody knows the price

In the US, if you want to know what a 2018 Toyota Camry is worth, you check Kelley Blue Book. There is no Kelley Blue Book for Nigeria. Used cars here trade through an informal economy: dealer clusters, WhatsApp groups, and listing sites where the asking price is an opening move in a negotiation, not a market value. Two identical cars can be listed ₦8 million apart on the same site, on the same day.

I'm building . If you're working on LLM products for markets the training data forgot, I'd genuinely like to compare notes.