For an unlocked device that can use a SIM (assuming you are going with a GSM device) from any provider, then $200 is pretty cheap. Take a look on Amazon.com. I have several, ranging from an old Nexus One (freebee from Google), to a Nokia 920 (freebee from Nokia when I left their employ), to a OnePlusOne which I purchased to replace the Nexus One. That one cost me about $350 USD, is very capable, has great battery life, 64GB storage, and 2GB RAM. I also have a company Samsung Galaxy S5 that has similar capabilities to the OnePlusOne, but also has a swapable battery and a micro-sd card slot.
Both the Samsung and the OnePlusOne should work on any GSM network (international) and I think they also have non-GSM capabilities as well, but I haven't tried that. I think I would need to visit Japan to find out! :-)