If you're looking to for a cheap android phone check out the Moto E, amazon has it for $150(it has LTE and an SD card slot). Link
If you're looking for a cheap smart phone, I've heard the Lumia 520 can be had for around $50. Link
Also I highly recommend swappa.com as a place to purchase good/great condition used phones.
Yes it will work with Ting GSM. You will need a Ting SIM card. Both the Universal LTE and US GSM (3G only) versions will work. Do not get the Global GSM one. I would go with the LTE version due to its newer processor and, of course, faster LTE data speeds, but it is up to you to decide if the cost difference is worth it.
I'm guessing you're looking at this: https://www.amazon.com/dp/B00TFAVFL4/
Most of the sellers are selling the AT&T model pre-unlocked or with an unlock code included. Additionally, the AT&T model can't be bootloader unlocked for root/ROMs, if that matters to him. Regardless, it has all the right bands necessary for use on Movilnet.