About CostCompare
If you have ever looked up what it costs to live somewhere, you have used a crowdsourced site — one where the price of a cappuccino in Lisbon is whatever the last person to visit the page decided to type. For an idle daydream that is fine. For deciding whether to move countries it is not evidence.
CostCompare answers the same question from the statistics offices: the World Bank's purchasing power parities and Eurostat's price surveys, with the working shown so you can reproduce any figure yourself. Where the two agencies disagree, the page tells you.
It is deliberately narrower than the crowdsourced sites. It will not tell you the price of a beer in a named city, because that is not something official statistics know. What it will tell you is solid.