This.
There are cellphone chargers on ebay that cost $1 and take AA batteries, which are quite capable of charging any phone that supports the USB charging interface. I bought one to use when I travel abroad and it works very well.
Please do not plug your $600~ smartphone into a $1~ charger. That's just asking for trouble.
Why? Do you think they'll fight because they don't make the same amount of money?
But fine, get a $5 model from a reputable brand.
You can also get an entire phone for $10. It will even have a screen!
Don't spend $50 on a piece of garbage.
You're assuming that supplying 5v to a cellphone through a 5v USB charger is something that damages the phone.