Which is better option for me?

I'm using iphone 5s right now, i don't like its shape, but i have no computer,
i think if i sell it i can buy iphone 4s and a used computer,
please tell should i keep it or sell it & buy 4s & computer?

Personally I would keep the iPhone 5s and save money for a computer.

Keep the 5s, or trade it in for an iPad, which is close to a computer

Computers are getting cheaper, however for some reason iphones really aren't that much cheaper. It would cost you the amount it takes to buy a new computer to buy an iphone 4s if you weren't buying it under a contract. So no, you should probably keep your 5s unless you just desperately need a computer.