I picked up an Eaton E-Locker for a D44 solid axle swap I'm working on, and even with the gears, and install kit, I'm just a hair over $1000 (this is with a hell of a friendly discount!!). This is not including my time to set the gears/locker up, or little things like oil. Remember that if you're going to get a shop to do the install, then you're looking at 3-4 hours of shop time to set up the gears.