Gaigaan-Dnok mentioned in the Best Toy thread that his Flagg PA system is broken and I realized I never posted something I did when mine broke. When ebay only offered ones for $50.00 or more I turned to amazon for this,
Spoke Heads Minin Megaphone with Mic. Is it exact? No. Is it better than a broken piece of junk. Yes, plus it has the mic feature which still lets you yell at people. Plus a siren which is awesome for waking people up in the morning.
I didn't start there though. I started by trying to repair the one I had. But not being an electrician and dealing with 20 year old toy that was built on the cheap to begin with led me to look into replace instead of restore. I then found a different bike horn, thinking I could just take the parts I needed to replace the broken ones on the Flagg's. Totally incompatable. They looked the same but they were not the same.
I tried the Spoke Heads one and while not 100%, it was close enough to work and look good. Ironically while the picture showed a yellow one, the one I got in the mail was the same shade of grey as the Flagg's. I can't tell you how awesome finding that out was. I wouldn't count on that happening as your mileage may vary for what color you get. A little switching out of the stickers and adding a battery later, and I had a cheap replacement megaphone with working mic for my flagg.
Matthew – 
Yahtzee!
Uno!
You sank my battleship!