I believe that was inherited from how the British pound sign is written: £100 rather than 100£ has long been the standard. But I don't know why, where, or when the British usage originated.

Maybe because: $1 25¢

So that's like writing: Kg 19 300 g

I understand it's tradition, but the fact that people keep using it kills me. Especially when people start using kilo $, and in "$ 100K".

Tip: It's written with a lower-case k. Capital K in front of B means 1024 to some people (including me), but 1000 is always written as k.

Thanks. You are correct about lower case k for kilo (but upper case for mega and up), but the official unit for 1024 bytes is the kibibyte, which is KiB:

http://en.wikipedia.org/wiki/Kibibyte

That's why I said "Capital K in front of B means 1024 to some people".