Try this walkthrough
One the first day buy 10 units of cups, 40 coffee, 20 milk, 50 sugar.
set the ingredients at max.
set your price between 4.00-$5.00.
match your prices with the weather for the following day.
whenever it's freezing or cold, you can increase your price between 5.00 to 6.00, and whenever its warm set it between 4.50 to 5.
your reputation will increase as the days go by, your reputation will reach its max either by the 5th or 6th day.
if your reputation is high enough you can have the option of setting your prices higher. On my first try i've made about 700.00 by the last day.
I haven't tried setting the price to 10.00 yet