I've bought two replica chargers for $20-30 off ebay.. i'm on my second. The first one lasted a year, which is about how long my original charger lasted due to the cord fraying
While a couple of them have died, so have my original three MacBook chargers. None of them has killed or damaged mine, or anyone else's MacBooks.
Here's a recent house fire that killed five people, started by a phone charger.
http://metro.co.uk/2015/06/10/phone-charger-started-fire-tha...
If you look inside cheap chargers (as I have), it's not surprising that they occasionally kill people.