BLU is an original equipment manufacturer (OEM) who I've heard makes decent phones at incredible prices and today one of their lower end/priced devices is the Amazon Goldbox special of the day.
For $50 you can pick up the BLU Advance 4.0 (unlocked). It also comes in a black version.
I would love to tell you more about this phone or point you to a decent write-up on it, but I know almost nothing about it and I can't find a write-up on it from a site I'd normally trust and go to.
I can tell you it has a 4-inch display, uses a dual core Mediatek processor, has 512 MB of RAM and comes with 4 GB of built-in storage (but has a microSD card slot) and Android 4.2 (which is Jelly Bean).
Oh yeah, it's also a dual SIM capable phone. For those who care about that sort of thing.
Beyond that all I can say is that if you're in need of a really cheap backup phone or one to maybe give to a relative or friend who still hasn't made the jump to a smartphone then this definitely isn't a bad price to do that.
This deal expires today, so don't slack if you're inclined to get it.
And let me just reiterate, because I got into a discussion about this the last time I mentioned a special on a device, I am not saying go buy this phone. I am not saying this is the best phone on the market or for that price point. All I am saying is that this isn't a horrible phone at that price point. Use it to listen to music. Use it to play simple games. Give it to a friend or relative who still has an ancient flip phone. I don't know. Do whatever you want with it. Or don't. Since I don't know if you'll get it or not. My "job" here is to just share noteworthy Android related news as it comes my way. /end rant