Relative Costs of Stuff

I still marvel at how some things are so incredibly cheap. And some things (electronic and electrical stuff, mainly) are double what they cost in the US.
Some examples of recent purchases: (equivalents in US dollars)
3 large avocados, 2 limes and a hot chili to make guacamole for a party $1.20
onion $.35 kilo
watermelon $.30 kilo
4 mangos to bake a mango cobbler $.90
1 kilo of organic brown rice $1.20
small bottle of organic sesame oil or tamari $2.20
8 ounce bottle organic shampoo or conditioner $2.25 each
ginger $1.00 per kilo
cauliflower $.55 kilo
ready made mosquito net for covering the top half of my bed $6.50
needlepoint scrim for painting, 45 inches wide $11 meter
cheapest available cell phone $75
set of cotton sheets with two pillowcases (double size) $30
can opener $2
6 cans of tuna packaged together $5.50
dressmaker services – two skirt waistbands $2.00
2.5 kilo bar of highest quality bittersweet baking chocolate (a cookie sheet size, about an inch thick) $11