Today is June 2018, my recommended affordable smartphone for this (and other Social Media Tasks) is the Xiaomi Redmi Note 5. This already has 2 cameras at the back.
This is not to be confused with the Xiaomi Redmi 5 - w/c has a lower megapixel selfie camera and only one camera at the back (approx 9,000)
Redmi 5 Specs Below (PHP 9,000)
Q: How about the MicroSD you talked about? Where do I get that?
A: It's 2018, don't go to the store. Just get it delivered to your home! Pick this one I selected: A 128 GB Microsd.
So how do you make the phone save to SDcard automatically? Here's a tutorial: