You don't need to kill anyone to get this Achievement
All you need to do is become a Werewolf
(Advance to a certain point in the Companions Quest Line and you'll become one)(At the end of their Quest Line you find out how to be cured)(Just make sure to take two head's instead of one)
Best thing about this is that you decide when to change into a Werewolf in the game (It's a Power that you can use once a day :D)
Now what you do is go to a Major City and just transform into a Werewolf. Boom 1000g Fine straight away :D Run Away (Note you run faster than a Horse in Werewolf form :D)
Then wait a day and go straight to the next Major City.. Lather Rinse Repeat :D
Here is some info on Werewolf's in Skyrim :D
http://uesp.net/wiki/Skyrim:WerewolvesSo yeah Good Luck
ShadowMonkey987..