Ok, 3DS or an Android phone of around 200$?
3DS are like 170, but either way I say 3DS for one reason only. In a few months your going to want a new phone again anyways, while 3DS should last you a few years at least. Seems every other month people want a new phone cause a new better one comes out all the time.
So if you can get by with your probably pretty nice smart phone you have right now, i say keep it for a little longer.