She drinks half a container of a 6 serving bottle of iced coffee a day so she drinks 6/2 = <<6/2=3>>3 servings a day
There are 7 days in a week and she needs enough bottles to last for 2 weeks so that's 7*2 = <<7*2=14>>14 days
She drinks 3 servings a day for 14 days so that's 3*14 = <<3*14=42>>42 servings
Each bottle holds 6 servings and she drinks 42 servings in a week so she needs 42/6 = <<42/6=7>>7 bottles
The iced coffee is on sale for $3.00 a bottle and she needs 7 bottles for a total of 3*7 = $<<3*7=21.00>>21.00
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