Usually a vets office will sell them to you, might uh...want to find a different vet though. That price still flabbergasts me.
IIRC we used lactated ringers with Vitamin B complex (AKA a 'banana bag'). Been a while since I helped with a parvo case though.
The vet didn't even give you a bill? Some itemized statement of how much they charged? Seriously, a grand for ONE overnight stay is absolutely ridiculous. You didn't go to an Emergency clinic by chance did you?
Oh and the Pedialyte is a good idea. I was going to say make sure you're giving him something with electrolytes in it as just water can make it worse, but couldn't think of anything with lytes that you could get at home and that was appropriate for a dog ("What flavor of Powerade does your dog like? I'm fond of the purple myself..."). If you can get him to eat then that'd solve that problem but it's really hard to get a parvo dog to eat much. That's another benefit of Lactated ringer's solution: it has the electrolytes in it.
Also don't sweat the IV line, they're extremely easy to use. The critical part is making sure the hose is clear of air first (run it for a couple of drops), after that there's not much to worry about other than height and making sure the dog doesn't chew on it. The hard part (getting it in the freaking vein) has already been done for you.