In the USA if I need a quick breakfast I grab a bagel with a spread for about $3; in China I will grab a noodle bowl for 3 RMB or a couple baozi for 2 RMB each.
Other points I use to come up with my recommendation that outside Beijing and Shanghai you treat 1 USD to be equal to 1 to 2 RMB.
Bus Ride - $2, RMB 1-3
Quick lunch - $8-15, RMB 10-20
Beer at a basic bar - $6-8, RMB 8-12
Beer at store: $1-2, RMB 2-4
Of course this is for domestic products in both countries. Imports cost more and follow exchange rate. For example, in China imports are usually exchange price + 25% import tax (electronics, cars).