Some items are over twice as cheap in Spain than the average in the US.

I was making breakfast this morning and I checked the prices of the items I use to make breakfast for my wife and I: eggs, milk, cheese, and bread. For all of them I found that one of the top 3 results was the one with the lowest price, and that one was a store called Mercadona. I live in Barcelona, Catalonia, so it's a brand available to me, so I used those prices. This is what I found:<br><br>1. Eggs:3.99$ per dozen (Mercadona) or 5.09$ per dozen in Walmart (according to Walmart’s website). This is a price difference of 31.3%.<br>2. Lactose free milk (important for me):2.58$ per liter in Mercadona, 4.33$ per liter in Walmart. This is a price difference of 67.7%.<br>3. Cheddar cheese: 5.36$ per kilogram in Mercadona, 11.54$ in Walmart. This is a price difference of 115.3 %.<br>4. Bread: 1.26$ per loaf in Mercadona, 2.48$ in Walmart. This is a price difference of 96.8%.<br><br>I used the exchange rate of the last day to make these conversions, 1$ = 0.88052€.<br><br>Edit. I feel like this post is being considered from a position of "you don't know Spain well enough". I am Spanish, from Barcelona, and I live in Barcelona. I am fully aware of what Mercadona is and what the prices are. I get my milk, cheese, eggs, and bread from Mercadona, regularly. I do however have the ability to consider through the lens of a hypothetical American that has never been to Spain and that's the perspective from which I wrote this post.<br><br>Edit 2. I am not claiming a change in the exchange rate is not possible, it's possible, and I could be wrong. I am not claiming that what is happening right now will continue to happen, it could be a short term movement. I am not claiming that it is sustainable, it could be not. I simply want to have an open, academic discussion on possible causes for this, and if this is the norm or not in the past.