I am aiming to do that very thing. This will be my big fall expense and am working hard at selling things in my eBay store in order to be able to offer cash later this year.
My son suggested a combination of drip and overhead depending on whether beds or lawn area. He thinks it will cost about $3000 (I have a very large yard and garden).
I had put off doing it in order to do other improvements and repairs, but the time and money spent this year has convinced me it would be a sound investment. I also need new windows, so I had better get cracking on selling!
You can actually do drip for the lawn area as well. It’s a bit more difficult when the lawn is already in but easily doable. In the lawn area is where the big savings will come because a lawn needs to be watered (with spray heads) multiple times per week due to evaporation and having to put down enough water to saturate the ground to the proper depth.
Drip done properly can saturate the soil deeply and force the roots of the grass plant to go deep where the blazing sun and heat will not have any effect on them.