Hi,
This is something that we must all face to the extent that we have taken our Buddhist Practice out of the monastery, and have given up the begging bowl as our primary means of support.
My advice comes down to two phrases: "all things in moderation" and "do not be attached".
First, there is nothing wrong with spending on the necessities and basic comforts to keep your family healthy, housed, educated and fed. Children need clothes, shoes, toys. But what about anything beyond that, like that Ipod?
Well, our Zen way does teach us to cultivate simplicity in lifestyle, and satisfaction from non-material things. The man who is content with what he has, no matter what he has, is ... thereby ... the wealthiest man in the world, even if he lives in a straw hut with no possessions. While we do not live that way in the Middle Class West, we should try to head in that direction as much as possible. The sun through the trees, just living, a child's smile, the sound of a bird call ... all are free! You should try to keep life relatively simple, and make do with what you truly need as much as possible, cultivating an appreciation for the intangibles instead of the materials whenever you can. For example, while a car is a necessity these days ... and even if you can afford a Porsche ... perhaps make due with an older or simpler car that is "enough"
Next, even if you have some expensive possessions ... a house, a car, jewelry and the like ... try not to need them, be willing to see them taken from you. That is non-attachment. If you are proud of your house, and fear its loss, you are not free. If you think your house is comfortable, but would just smile if it burned in a fire, you are free. In our Buddhist Practice, we know that "all things are change" and "nothing lasts" ... so we cultivate a flexible mind that is will to allow that should it happen.
And yes, do charity work, contribute, volunteer as much as possible. Do something to make the world better (through your job or outside activities) to make up for the blessings you have received.
I think that we cannot get away from materialism so much in our modern lives, but we can keep it in some balance and avoid excesses.
That is what I recommend.
Gassho, Jundo