Getting your dollar's worth of food!

Following on the One Dollar Diet Project's footsteps, Amy and Karla of Hope Heals:"Dollar-A-Day Challange" are attempting to eat on a dollar a day for a month in order to raise money for a trip to Africa with Habitat for Humanity.
One point raised in the $1 Diet Project's comments is that a dollar a day buys you more in those very countries where people live on that amount of money or less, countries such as Mexico. I was curious so I took Amy and Karla's shopping list and compared it to the prices listed on Profeco's website Quién es quién en los precios (who is who in prices) where they comparison shop a wide list of items.
Here is the blog post for Hope Heals' first shopping trip
Here is their list and the comparable items I found. I used the least expensive prices for comparable items. They didn't give weights for most items but I have. I used $13.00 peso per dollar as the exchange rate and 2.2 pounds to the kilos.

1. bag of red delicious apples $2.79 Starking apples which look like red delicious to me are $24.90 p/k or $1.92 usd
   
2. head of iceberg lettuce $.99 $1.90 or $.15usd
   
3. package of ground turkey (no weight given) $1.19 Turkey is a luxery meat here in Merida, so I compared it to ground beef at $36.00/k $1.26 usd p/ lb
   
4. instant corn masa (no weight) $2.39 a kilo of Maseca brand is $6.20 or $.18 *prepared tortillas run from $5.38 to $11.00 a kilo or $.19 to $.38 usd a pound.
   
5. canned corn (no weight given) $.49 225 gram can of corn is $5.90 or $.45usd
   
6. hot sauce $.79 Salsa picante La Costeña 370 ml $6.10 or $.47 usd
   
7. 30 eggs $2.99 or 2.9c each the tienda across the street has the best price on eggs $.10 each or $.0077usd each
   
8. pinto beans 64 oz $3.29 or $.0514 per oz $12.35 per kilo or $.027 usd per oz
   
9. rice 48 oz $ 1.99 or $.0415 per oz $12.90 per kilo or $o.0281 usd per oz
   
10. salt and pepper $1.00 salt is $4.10 per kilo and ground black pepper is $20.50 for 60 grams or a total of $1.89 usd for a whole lot of salt and tiny bit of pepper!
    
11. large can tomatoes $1.00 *the only canned tomatoes that I have seen are imported from Italy and probably cost more than $3.00 usd a can. Whole fresh romas are around $16.00 a kilo right now so a pound would cost $.56 usd.
    
12. ranch seasoning $.33 no comparable
    
13. taco seasoning $.66 no comparable
    
14. 16 cheese slices $1.00 not on the list
    
15. bananas $.10 each $4.90 per kilo or (I weighed a banana it's about 8 to the kilo) or $.047 each

I totaled their expenses at $14.6429 (by unit) and my costs at $7.138 (leaving out the seasoning and cheese) So with the exception of some exotic things like apples (they are imported from other parts of Mexico or the USA), canned tomatoes (fresh are cheaper and available year round) and the spices and mixes. My dollar a day would buy at least twice what theirs does unless those apples are in a five pound bag then my total is $9.578 (one and half times more food) but if they really scored big on those apples and got a ten pound bag then my total would be $13.938.