
I only paid $99 for each of my half shafts at NAPA. I did need to rent a hub puller and purchase a 36mm socket (I think that's right). Other than that, I agree with JJ, if you installed your own lift then you'll be able to replace your half shaft(s). There are just a few extra steps to take. You might also find the repair manual useful.
Be advised, if you're running your axles at extreme angles, take further precautions like the ones mentioned by some of the other users. I can't attest to their effectiveness, but I know I've read some recommendations in the past such as, pulling the boot down slightly to reduce the accordion affect (watch the clevis) and spraying some type of silicone lubricant on the boot to reduce friction. That should hopefully, at the very least, help keep the boot intact and the grease where it is needed. Keep a watchful eye on them in the future. If you don't change something in the formula, then expect the same process to repeat itself.