IPhones, SIM cards, microSIM, contract, and go phones?

Okay, this might get confusing so stay with me lol.
I have a prepaid android (at&t) and got a new android. We're giving the old android the my brother in law (he has a contract through at&t). He is giving me his iPhone 4s. I got a new regular AND microsim and need to know how to activate them both without locking them to the phone. Any ideas? Please help!

Added (1). How do I activate them? Online or do I just call?

Got a used iPhone, switching to AT&T?

My friend is giving me his old iPhone, but I'm not an AT&T customer. I have an android on Metro PCS and I want to switch to AT&T to use the iPhone. How do I got about in doing this? What would be the monthly costs if I wanted unlimited talk/text on this iPhone? Please, someone give me a detailed answer.

How to cure chronic eye strain?

I started getting this after getting an iPhone and using it to do work. It's been around for about 6 months now. How can I cure this?

An i upload photos on webstagram?

Ok so i know i can get on instagram on my computer (webstagram) but can i upload on their or can i only upload on regular instagram on my iphone

Confused about following people on instagram? - 1

Actually, InstaDesk, more specifically because I signed up for Instagram on my friend's iPhone and I don't have one myself.

So I'm trying to ''follow'' two of my friends, who I know in real life. My computer asks me if I want to ''send a request to follow them''. I said yes to this and then I was able to click the ''follow'' button on their pages…

But then like a few minutes later, I went back to their profiles out of boredom and it says ''follow'' again…

This is weird though because I requested another friend last night, it was doing the same thing, but now we're ''following'' each other…

What happened here, honestly? What happened with my requests?

Added (1). Was it because I was never actually ''following'' two of my friends, and just ''sent a request'' to follow them?

Can i resell a locked iphone 4 at&t?

I recently bought an old LOCKED iphone 4 at&t off of my friend (stolen) and i'm trying to resell it for a higher price. Can i sell a locked/(stolen) iphone on gazelle or ebay or any of those kind of sights

Can i resell a locked iphone 4 at&t? - 1

I recently bought an old LOCKED iphone 4 at&t off of my friend (might be stolen) and i'm trying to resell it for a higher price. Can i sell a locked/(maybe stole) iphone on gazelle or ebay or any of those kind of sights

What are some good iPhone gamecenter games?

I need some free iPhone games that are on gamecenter and are fun I already have temple run 1&2 and fruit ninja I need some others I looked at the top free but doesn't show anything so please give me feedback