What does HD vs SD mean?

I was going to buy the movie 'Mean Girls' on iTunes, and the movie is $17.99. Then I noticed a little button that said SD and I touched it and the price went down to $9.99. What do these things mean, and which should I get? I'm on an iPad, by the way. Thanks. (:
>>> What does HD vs SD mean?

What does airplane mode mean?

Like on phones or iPods or iPads? Or any kind of technology that has airplane mode
>>> What does airplane mode mean?

How to stop technology from babysitting?

My family likes to use TV, movies, ipad, computer, and other tech to keep my baby brother busy.It pisses me off, but I can only take care of him myself for a few hours a day. I need advice on how to confront my family members and persuade them (it's difficult because they're into the virtual as well--it's often how they spend their down time) to get off facebook or instagram and actually raise him.

This my sound strange given that I'm asking everyone on the INTERNET, but I'm afraid that when I leave home, I'm going to find a potato instead of what used to be my sibling.
>>> How to stop technology from babysitting?

Im jealous that my best firiend got the iPad 4?

My best friend got an iPad 4 and Im really jealous. I know that Im not that much of a friend if Im jealous but I am. I really wanted an iPad 4 and now she has one. She is my best friend. I dont know how to not feel jealous that she got one.It will take me awhile to get used to her having one but I need to know how to deal with it now. Please help.
>>> Im jealous that my best firiend got the iPad 4?

My wifi is SLOW! HELP?

My wifi has a password and my dad is currently on his ipad, I'm on my laptop and my ipod and my brother is on his laptop. Can this cause our wifi to be slow? How do i speed it up?
>>> My wifi is SLOW! HELP?

IPad vs MacBook Pro (Mac Users only please) .?

If you are only wanting to use a computer for Internet (SKYPE, WEB BROWSING, EMAIL), what do you suggest? If went for an iPad route, do we still need a cable connection / air port express/extreme LAN device ?
>>> IPad vs MacBook Pro (Mac Users only please) .?

If you could develop the iPad in any way you wanted what would you do to it and why?

Just curious :}
>>> If you could develop the iPad in any way you wanted what would you do to it and why?

What are better, iPods or iPads?

What are better, iPods or iPads?
>>> What are better, iPods or iPads?

How to get wireless connection upstairs with router in basement?

I want to get wifi for my Ipad upstairs in my room but thee walls have metal in them and the router is 2 floors down (in the basement) how can i get wi-fi up to my room?
>>> How to get wireless connection upstairs with router in basement?

I know this sound silly but how do you save?

I'm trying to save up for an ipad but how I've just had a birthday party and I got £45 that's not enough and I get paid £7 a week but I just end up spending it I've saved £55 so far help
>>> I know this sound silly but how do you save?