The new cell phone space is VERY competitive. In order to make any kind of profit from cell phones sellers either need
1) large volume purchases
2) a way to bundle or upsell the buyer
3) or some other way to attract buyers to your service (like some kind of service you offer with the phone).
It is unlikely that sellers can compete on price alone with small volume purchases.
If you have technical skills, you MIGHT be able to buy wholesale lots of damaged cell phones, buy parts in bulk and fix them up, and then resell used phones to buyers and make a profit but it takes some research and confidence in your own skills to do this.