It's over 12months since i bought my gears, but i bought my 4.11 diff gears from wooders. $320 for the dana30, $360 for the dana44 thick cut, and two install kits at $175ea and wooders gave me a bit of a discount because i also bought a sye, driveshaft, adjustable control arms etc at the same time. I then paid $750 labour for both diff ratios and a front air locker to be installed. Plus about $30 diff fluid
This was over 12 months ago when the $au was 98 cents per $us so i dare say it'll be a hell of a lot more expensive for poor wooders to import & sell than back then.
Does that help?
cheers