What's the cheapest way to buy iphone 6 to use?

What's the cheapest way to buy iphone 6 to use?

Added (1). i need to unlock to use in my country, so what's the cheapest way to buy an Iphone 6?

Added (2). brand new Iphone 6
which country sell it cheapest i'm from sri lanka

Is my iphone completely ruined?

So I dropped my iphone and the screen cracked a lot. The display still shows, but there are multicolored lines across the entire screen, and there are black spots around the two main cracks. I can still read some of my home screen, but the touchscreen doesn't work. Is my phone completely destroyed or will I be able to replace the screen?

Why is my iPhone 4 slow sometimes?

Is straighttalk the reason for my iPhone 4 being slow?

For starters, I play respawnables which is a mmorpg or a rpg which ever, on my iPhone 4. And when I try to play on multiplayer, it says I can't connect to server. My speeds is fast when not throttled. 3mbps. And I'm on straighttalk. Still locked to AT&T. When I do play multiplayer, its when using Wi-Fi. Maybe 2 times I've been able to play multiplayer on my phone on it's on but still had connection problems. I thought it's because my phone uses 3G but my uncles phone uses 3G, an android, and his phone can play respawnables multiplayer very smooth. And it's on sprints prepaid. It's a Motorola Moto G. I'm starting to think it's because of straighttalk. And because my iPhone 4 is old. But how fast my phone loads data, I don't think so. I've been wanting to get a new iPhone 5s because of this. Not just that though. There's other problems with this It also loads some web pages slow sometimes or not completely right.