There is 2350 verses in our Bible about "stewardship" ($ and possesions). Jesus himself spoke more about this subject than almost any other. In contrast, the Bible contains around 900 verses on "salvation".
Our God IS concerned about how we handle money. He is aware how much of our lives depend on money. He knows that money can take His place in our lives as an object of idolatry. That is why he speaks so much about it.
But in God's ecconomy, all the money in our account is really His money. We own nothing, but rather are appointed stewardship over it. Once you realize that it is God's money and not your own, you start to be more careful how you spend it.
Use this test...If, knowing that it is God's money, you'd be willing to spend it on that while he is standing rite next to you, then it's probably ok. If not, then you better reconsider.
There are several books written about using money the way God intended. Goto your local Christian bookstore and buy your freind one of these. I'd suggest one for yourself as well.
Some verses to concider...
Eph 4:28
IIThess 3:12
Prov 31
Phil 4:6, 19
Psa 24:1
ITim 5:8
2Cor 8-9
Gal 6:6-10
Matt 6:11 ITim 6:8
Ex 20:18 ITim 6:9 Heb13:5
Prov 28:20,22
Prov 13:11
Prov 15:27
ICor 8:9,13
I just finnished a biblical financial study...can you tell? lol