Can i use iphone 4 apps without Wi-Fi?

I have these music apps that arent connected to the enternet but i worry my data plan will go up if i use it at school or in the bus. Do i need Wi-Fi to use those kinds of apps?

Iphone/ipod problem.charging and syncing?

I have an iphone 3gs(yes, i know its old)
and an ipod touch 4th gen(not so old)

two days ago, they were both charging and syncing to my laptop Perfectly normally. Then i noticed my iphone started not charging as well, i have to turn it off and on several times to get it to charge on a wall charger. Even more strange, even though it was perfectly fine the day before, my iphod touch won't even charge at all on a wall charger. It lights up when i plug it in, but never charges.

then i tried to connect it to my itunes. My comp says "device not recognized" i've re installed and restarted took the battery out, everythign and i can't for the life of me figure out why this is happening.

any help out there? (please, in simple terms, i'm not the smartest in technology terms)

I can't download apps on my iphone

I want to download some apps but it says "billing information". I can't fill it out because I don't know the security code (only my parents since they bought it). And also they aren't home right now: P how can I download apps?

Where can I find good deals on Vera Bradley cases for an iPhone 4S?

I just got a Vera Bradley case for my iPad 2 in the pattern "Limes up" and I wallet with an iPhone holder in the same pattern. I'd like to find a matching case in Limes up for my phone, but I really want to find a good deal. Also, can you recommend any other cute cases?