So you think the screen is kaput or doesn't look 100%.
There's a few very good phones around the 300 mark now, discounted or online. You may find the Nexus very different to operate compared to a Samsung. I would consider the Moto X or S4 if available around that price also. The Nexus looks good on paper. I will let others advise you. It may not get noticed here though. If you have the time I would start another thread asking that very question but perhaps? on another Forum, I don't know, Central Lounge, Nexus 5 or OK actually here also.
You would need to buy that one quickly, you may already have done, and sell the N3 later. Some will put you off Craigs List, like Gumtree here, but you sound smart enough!
Unlike what a girlfriends mother or your mother-in-law used to tell you - DON'T keep it in your pants next time.
(no, that wasn't very good

)
Via my Note 3 on AC.