I'm spoiled as I live by the Gilbert location so any time I need some landscaping rocks I drive on over with a few buckets and get what I need. I've only ever hauled my own rocks. It's a really simple process. Weigh in, load up with a shovel and weigh out. Insanely inexpensive prices for my small needs. When I go I'm only purchasing about 300 pounds worth.
My only suggestion is I wish they had longer weekend hours.
Make sure they know what you are getting as the price can easily double if they ring up the wrong thing.