IPhone Payment Plan? Real Thing?

I saw that AT&T, T-Mobile, and Verizon are offering payment plans that split the cost of the phone over 20 months, but you still have to sign up with them for service. I'm looking for a payment plan for an iphone, but have it be unlocked so I'm not required to pay for the phone AND service if funds are short some months. Is there anything like this? I can't afford $600 down.

When I upload a video on Instagram it says 'failed'?

When I upload a photo on instagram, it works fine. But when I upload a video on Instagram, it always says 'failed'. I tried switching from my iPhone and iPod, 3G to Wi-Fi but it still doesn't work regardless.

How to download songs to my music library?

So recently I pre-ordered Katy Perry's album Prism, and a song from the album came out today called Dark Horse. I go to iTunes and I click on the song Dark Horse but it doesn't appear on my music Library, the only thing written beside the song is "PURCHASED".So how can I listen to the full song from my Music Library? Do I have to download it or anything? (I tired doing that but I failed)

Ps: all of this happened on my iPhone 5, not the laptop.