Cricket (AT&T) has the
iPhone SE 64GB for $229. While it will be locked, if you switch to their Unlimited plan, they will unlock it immediately. So you can buy the phone with a month of service (even the cheapest plan), get down to the last few days and switch to the Unlimited plan (they prorate the plan, so you're just paying a few dollars extra), and request the phone be unlocked. Or, you can buy the Unlimited plan when you buy the phone, get it unlocked immediately -- you can even then downgrade your plan after (though the difference will be added as a credit to your account).
I also say buy the SE now, as long as you buy one of the discounted SEs. While Apple may come out with a new version, it will likely cost at least double compared to what the current SE is selling for.