Contact
Pricele is run by one person, and email is the only channel. Every message gets read; most get a reply within a few days.
Reporting a price that looks wrong
This is the most useful thing you can send. The prices here are national averages from public datasets, and if you live somewhere and shop there regularly, you know things the dataset doesn't.
To make a correction actionable, include the country, the item, what you actually see locally, and roughly where, such as a supermarket chain and a city is plenty. If it's a big discrepancy rather than a small one, say so; that usually points at a unit or currency problem rather than ordinary regional variation.
Before writing, it's worth checking the methodology page. Some gaps are expected rather than errors: local-currency figures for most items are converted from US dollars at the collection-date exchange rate, the Big Mac figure for eurozone countries is a euro-area average rather than a national price, and the work-time figures rest on wage estimates that are deliberately rough.
Suggesting a country or an item
There are currently 16 items across 49 countries. Both lists can grow, and suggestions are welcome. The main constraint is source data. An item needs a public dataset that covers most of the country list on a consistent definition, otherwise it can't be compared fairly. A country needs coverage across enough items to be worth a page.
If you know of a well-maintained public price dataset that would fit, that's an especially useful email.
Everything else
Bug reports, accessibility problems, questions about how the game works, press enquiries, advertising and partnership questions, and privacy or data requests all go to the same address. For privacy requests specifically, the privacy policy sets out what is and isn't stored. In short, your game results never leave your own browser, so there is usually nothing on our side to delete.