[mkl]

Dollar signs go before the number, not after it like units. It needs to be 1000 pages/$1 to make sense, whereas 10km and 10h and 10/h all make sense so 10km/h does. I imagine you would be confused by km/h 10 but not $10.

[ekwav]

In the EU we put the € symbol after the number so it feels more natural to do that for $ as well.