I have an 80 240D with the same problem. Here's what I've found out.
The boots are about $10-$15. It's the hassle of removing the "cans" that's the problem. Call around to some local shops that rebuild CV joints. Saw a post where they were able to get a local CV shop to install the new boots for $70 per shaft. The guy had to provide the boots and do the R&R on the shafts.
Another alternative is a split boot kit. I know this is heresy to some but have seen others say they work great. Suppose to be able to install without removing the shafts, but I think removing them is the easiest in the long run.
The best solution is to buy a used set, have new boots installed, remove the old ones, install the new ones, save the old ones for next time. This way you're back on the road in a day.