Newbie question water quality

My wife and I are new to the aquarium world and setup our first aquarium a
couple of months ago. We're having a terrible time getting the pH level
down to where it ought to be (we have a plain tropical, freshwater
aquarium - 46 gal). It turns out that our municipal water is just too
high a pH and not good to use in the aquarium. The pet store folks
suggested using distilled water. This is fine with me, but I'm not sure
how to go about this. I don't want to lug a zillion 1 gallon jugs of
distilled water from the supermarket and am looking for other options. Is
it convenient and/or cost effective to get home delivery of dist. water?
To somehow make my own? Will bottled drinking water work instead? I'd
appreciate any ideas from anyone who's grappled with this in the past.
Thanks!

greg d