Virgin mobile phones?

hey guys so my parents are going to get me a new phone. I have the rumor touch and im going to trade it for cash. My parents dont want to give me money and theyre making me work for it (peeling cable mostly) and making the money. So first how much money should i get for it and it has a little nicks on the screen. Secondly which phone could i get. I could convince them for like no new phones from there on if i cant get a phone for like 30 or 40 bucks to get extra money to afford it.

I would prefer

samsung intercept

htc wildfire s(my favorite but most expensive)

lg optimus v

so give me advice on both questions and give me tips how to persuade them to lend me money for any phone if i cant get it from the rumor touch money