Compared to full retail price, no you will not resell it for anywhere close to what you paid for it seeing as anyone with an upgrade can get the same device for hundreds cheaper. Even if they didn't have an upgrade they could simply add a line to their plan for $10 extra on their bill and get the phone and then just put their current number on that new phone and change the new line to the cheapest plan possible and still overall pay less than what the full retail cost is.
The only way you are going to come out in the green on reselling an iPhone is if you bought it with an upgrade price, not full retail, and then tried to sell it within the next two years. After the next to years you may break even or sell it for a loss.
I bought my 16GB 4 for $200 when it was released, sold it 16 months later for $300 to get my 32GB 4S. Sold the 32GB 4S 2 months ago for $360 and I priced it low because I wanted to sell it fast to recover the cost of my 32GB 5, otherwise I think I could have held out longer for $400.