Help/Support 2 New in Box 5s's ios 9.3.3 $130!! (straightalk locked?)

[Grandma 65 0 iPhone 5s 9.3.3]

I'm not sure if I should be excited about this or not.  I've found 2 iphone 5s's for sale for $130 bucks.  They are brand new never taken out of the box, never activated, nothing.  They were purchased from walmart 16 months ago May 2016. That puts them right in the ballp[ark of being ios 9.2 - 9.3.3.  It was August  I believe when 9.3.5 came out.  So I'm geeked about fresh jailbreakable phones, but they have straight talk sims.  Seeing as they have never been even charged, is there some way possible to use another carrier or unlock this phone?  If not, would there be any reason I would want to avoid this deal?  And can I get a confirmation that I should be able to download the Pangu/PP app to install Cydia?  I'm supposed to be buying them tomorrow night.  Thanks for any input