A Hamburger Today did some calculations for us on a meat-per-dollar ratio in their Bi-Coastal Side By Side Test. All prices are taken from New York and San Francisco locations (USD).
In-N-Out: $3.05 for a Double Double with two 2-ounce patties. Price per ounce: $.76
Five Guys: $7.09 for a cheeseburger with two 3.3-ounce patties. Price per ounce: $1.07
Shake Shack: $4.75 for a 4-ounce Shackburger. Price per ounce: $1.19
Based on my burger tour over the past month in Singapore, here's a quick summary for the city's offerings (SGD):
Average price per burger: $10.00 - 25.00
(not including US franchises, such as McDonald's)