The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Marco Siino:
Easy calculate the discounted price when you shop, or the percentage of a certain generic value!Percentize! is the easiest percentage calculator that allows you to calculate percentage quickly!* Calculate Discounted Prices: how many times do you saw "30% off", "20% off" and so on when you are in shops ? Percentage let's you calculate the discounted price easily, just type the full price and the discount percentage, et voil... percentize tells you the discounted price!* Calculate the percentage of certain values: want to calculate how much is the 74% of 1923.45 ? Just type 1923.45 and move the percentage slider to 74%, et voil... Percentize tells you the result!Percentize is a free useful tool that anyone should have on their iPhone, iPad or iPod Touch!