WALMART HAS A NEW STRAIGHT TALK SPACE GREY LOCKED TO STRAIGHT TALK 32GB IPHONE SE for sale at $159.00.
*Note these are locked to straight talk, first sim you put in the phone. (can be a ST Verizon sim which is included in packaging., or a ST AT&T Sim or a ST Tmobile Sim both purchased separately, but the first sim you put in will lock it to that ST carrier. I have also tested this by putting in an AT&T ST sim and then an AT&T sim and they both work in it.) These might also be easier for 3rd party unlock options compared to the new AT&T go issues. These are brand new phones with 1 year apple warranty.
Good luck at $159 for 32GB isn't a bad deal at all, not sure if there are better out there right now.