Question
Thanks for volunteering!

We're having a fence installed in our yard and the company that installed our irrigation system wants to charge us $100 just to come out and mark the irrigation lines so they are not damaged during the installation of the fence.

Is there any way that I can do this myself without spending too much money or no money at all?  If so, how?

Thanks,
Paul

Answer
Well... without a lot of digging the answer is probably no. Since the lateral pipes going to the sprinklers do not generally have a tracer wire with them, they need to be located with a shovel. The mainline pipe does have the control wire, hence it can be located with a wire tracker.
If you have an as-built plan of your system you can dig up a sprinkler figure-out which direction the pipe is running the go to the next head and do the same. You would need to do this with each head in the areas of the fence. Not an easy task. I would ask your contractor if they will be locating all the pipe or just the mainline. The mainline is critical, if it get cut and dirt get into it, you could have valves problems, which is the subject of many questions in this forum.
Sorry, I can't be more help. It's probably worth the $100 to have the pipes located. Though, even then there is no guarantee something won't get cut.
Matt