It's frustrating how much fish wind up costing and I have been snapped at a few times myself on there. As young adults and adults a lot of them have forgotten how resticted you are when you count on your parents (who think it's 'just a fish') for funds for an adequate setup. They overkilled, but other than their approach their advice is totally solid and worth taking. Frustrating but true... what good would a little penicillin do you if you were spending the winter outside in your tshirt and shorts?
Like I've said before, save your money, don't monkey around with different mediactions. Keep the water pristine and try to hang in until your birthday.