She uses 4 hours/day * 125 watts/hour=<<4*125=500>>500 watt hours/day
That means she uses 500 watt hours/day * 7 days/week = <<500*7=3500>>3500 watt hours/week
This is 3500 watt hours / 1000 watts/kw = <<3500/1000=3.5>>3.5 kw hours
So her TV cost 3.5 kw hours/week * $0.14/kw hour = $<<3.5*0.14=0.49>>0.49/week
#### 49