You can get Eaton Posi's on Evilbay for $375. The Yukon DuraGrip 'Eaton copy' can be had cheaper, Yukon Axles are good also & cheaper than most. I shopped around for cheapest prices then went with 'Complete Offroad' for all my Rear parts, Free S/H & they Beat or Match others prices. This was several Yrs. back & they beat the cheapest I found.
QuickPerformance seller name "staticz2229" has some smokin deals on Posi, Gears & Install kits 'package deals' on Evilbay. I'd check to see what brand Bearings the kit has tho'.
Yukon's Master Install kits are the better kits, they have Timken Bearings & the Super Shims.