After paying full dealership price for these, I vowed to find them on-line, and found a cheap source. I have found the splined spacer for $2.04, and the snap rings for 68¢.
The spacer is a slightly different design. The older spacer has a tooth for each spline groove. This one has only 6 teeth, in pairs, spaced around the inside diameter. I slid one on an axle yesterday and it was a good fit. I'm not sure if fewer teeth matter... it seems to me like there shouldn't be much force on this washer, but I have read some people have dished them. Anyway, for $2, maybe it's worth having a couple in the toolbox.
www.diffsonly.com
Axle spacer (they call it a spindle washer) WRN37891 $2.04
Snap ring DS42768 $0.68
It appears they only ship UPS, so I would look around the website for any other bits you might want.