Jezebel needs to buy 2 x 12 = <<2*12=24>>24 red roses.
Twenty-four red roses will cost 24 x $1.50 = $<<24*1.5=36>>36.
Three sunflower will cost 3 x $3 = $<<3*3=9>>9.
Thus, Jezebel will pay $36 + $9 = $<<36+9=45>>45 for all those flowers.
#### 45