The duct tape job on my site was more of a joke than anything. it lasted about 2 blocks.

I was bored that day and saw it, so I thought I'd tape it up and see what would happen.
$400 is highway robbery for this.
the left side axle is a 15 min job, and the right side is maybe a 30 min job.
you're looking at an hour at most for both axles, and they run $60 from most parts stores.
you should also replace both seals on the transmission, and they're around $10-15 each.
new transmission fluid wouldn't hurt either and there's about $20-30 in fluids.
that puts parts at ~$160 and 1 hour of labor (typically about $85). So if you pay more than $250-300 for the job, you're getting taken.