According to the prices given in this post by dansunoiruka (and the Naruto wiki) plus the assertion that 1 ryo equals 10 yen, here are the (approximate) conversions of the wages shinobi may get for each mission from ryo to Japanese yen (which is simply multiplying by ten, but is nevertheless included) and U.S. dollars (according to the exchange rate of August 2014).
D-Rank: Between 5,000 and 50,000 ryo (between fifty-thousand and five hundred thousand yen) - between $481 and $4,811.
C-Rank: Between 30,000 and 100,000 ryo (between three-hundred thousand and one million yen) - between $2,887 and $9,622.
B-Rank: Between 150,000 and 200,000 ryo (between one million five hundred thousand and two million yen) - between $14,434 and $19,245.
A-Rank: Between 150,000 and 1,000,000 ryo (between one million five hundred thousand and ten million yen) - between $14,434 and $96,223.
S-Rank: Upwards of 1,000,000 ryo (upwards of ten million yen) - upwards of $96,223.
Hopefully this provides a little bit more contextual reference both in yen and dollars for shinobi wages.