How to sell a new found iPhone?

Okay so i was walking my dog and I stumbled upon an iPhone 5s in an otter box case, and I was gonna call someone off the phone to return it, but it hadn't even been set up yet. The phone was still brand new like when you first buy it. I want to keep it now and sell it, but how would I do this? What if it's reported stolen? What should I do if it is stolen? Or is this whole thing just too good to be true?

Is the iPhone 4s still capable to run smoothly?

I'm looking to get an iphone that isn't that expensive compared to the newer models. I was thinking the iPhone 4s as I can buy a rarely good conditioned one for about £150. Is it worth it? Is it still capable of running with not much lag? Or should I save up or a newer model?

What should I buy with 3000 dollars?

Hello I'm 14. I already have a Mac Book Pro, an iPhone 5s, a car for when i turn 16 and so much more my dad is a millionaire. He gave this money to me for my birthday and i'm bored with it i already spent a couple hundred on shoes but what else?

Apps to download music for free on iPhone 5s?

I'm going on a really long train journey and I've just got a new phone so I have music.

Does anyone know any apps or something that I can download music on?

Also I need to be able to listen to the music without internet!

How to fix this iPhone drama?

Within the past month, I've dropped my iPhone 3 times.
When I go on certain websites, sometimes my phone will close the window of the website I'm on and will revert back to my home screen.

What can I do about these things?

My IPhone 4S screen is flashing?

The Wi-Fi wasn't being connected properly, so i turned of Wi-Fi and turned it back on again, that didn't work.
I tried turned off my phone and turned it back again, still didn't work.
Then I reset my phone. But when I turned it back on, the screen was flashing.

Can anyone help me please?

Where should I sync my note 3?

I'm in college and have a duel platform Macbook Pro. One side is windows and the other is Mac. I keep all business and school and purchasing stuff on the mac side and all my personal like photos and all my music stuff on the mac side. I had an iPhone and and just got the note because it is good for business. Now I'm split because half of the stuff I want for the phone is on one side and half is on the other. Which should I go with?