Thanks for the recommendations. I live in Torrance, so I ended up going to a Middle Eastern grocery store in Redondo Beach (on Artesia). The bottle of orange flower water turned out to be larger than I expected (10 fluid oz), and it was only $1.99!
I've seen it at Bristol Farms. Its an ingredient in some cocktails so you may find it at a place that sells liquor like a BevMo. Comes in a small bottle like 3oz-4oz and can't imagine its more than $5 for a bottle.