underground sprinkler - or another option?

My parents have a VERY small yard & are interested in a possible underground sprinkler system.  Has anyone had one recently installed?  If so, what was the cost?  Has anyone done it themselves?  If so, is it difficult/complicated?  And lastly, is there another option for when they are not home for long stretches of time during the summer...that you'd recommend (not interested in hiring the local kid to water the lawn at this point). Thanks!

I love mine but I can’t remember what I paid.  Maybe $2500?   but then you can throw out all your hoses and sprinklers and never have to drag them out.   There is a small fee at the beginning and end of each season.  Maybe $75.  

We have used a sprinkler timer, which you can purchase at Home Depot (although we got a fancier one online at dripdepot.com).  It hooks up between your outdoor spigot and your hose.  You set up your regular hose and sprinklers as needed, program the timer (with ours, the least amount you can program is once a week, the most is four times a day every day).  Turn on the water at the spigot, and then the timer does the rest.  I wouldn't leave this alone for the entire summer, but it would be good for being away from home a few weeks at a time.

I use the electronic timer for a sprinkler, that covers my outdoor orchid benches (about 1000 sqft).  Last year I set it up in late April, and it worked without a hitch till the plants have to come back into the greenhouse in October.

This year I have expanded (2nd orchid range + a field with cantaloupe & pumpkin), so I need to control 3 sprinklers.  I do this with one controller that controls 2 hoses, and another for the single.