$50 Asus Zenfone 4 - worth it?

I'm going to be leaving the country soon and I need a phone with a sim card slot...(believe it or not, my current phone does not)

So, I found an Asus Zenfone 4 for $50. It's got some scuffs and scrapes - nbd. Seller has a very long and reputable selling history. Says the phone is 100% functional and unlocked.
I really don't want to spend much more than $50, so I'm wondering if this is a good deal or not.

oh and it has a clean imei (according to the seller)