I totally understand where you are coming from!
There will always be kids who have parents who can afford (and are willing!) to buy them the latest and greatest in technology.
It's hard not to get angry at your kids for wanting these things, but I try my best not to get too mad when my daughter "gets sad" because she doesn't have the latest-and-greatest. It's just normal to want something. Heck, I want a bigger house and a nice car.
It's not a crime to WANT something. So be sure to let your daughter know it's perfectly normal to WANT something. It's just being a human. We want stuff!
But it's not okay to be ungrateful, or to make the people who are working hard in your life feel bad because they can't afford or don't want to buy you something.
Be sure to validate the feeling of wanting. It's okay to want. It's just how you handle it that matters.
My daughter has a LOT of nice things. She was the first of her friends to get a phone (it was a 4 button phone that only dialed 4 pre-programmed numbers) and she got a phone because she'd go to her mother's house and sometimes she felt unsafe so she had a phone so she could call us at any time. (It's a sad day when you send your SD to her mom's house and you have to worry about her safety but there's nothing you can do).
She has an iTouch. It's the older model so there's no camera attached. Some of her friends have a camera on their iTouch and she got sad because she didn't have a camera on her iTouch. I wanted to get mad and FREAK OUT because we had to get her an older model iTouch because we couldn't AFFORD to get her the newer model and she was lucky that she got ANYTHING!
But instead I let her know that it's okay to WANT something. But it's not okay to make us feel bad in any way because we worked HARD to afford the iTouch she got. I didn't yell, I didn't freak out.
She actually felt BAD about how she acted. I think if I had yelled she would have just ignored it or refused to LOOK. But because I was both understanding and disappointed, she felt bad.
My SD is only 11, so she still doesn't have much of a concept of money. But she's much better about asking for expensive things or whining about them.
Good luck! Sometimes your child won't understand how good you were to them until they grow up. I look back and see how much my parents sacrificed for me, and I wish I would have been a little more grateful at the time. I think we all do.