Yes a Cydia App after quite a long break. Easy Loan is a Simple, easy to use loan payment calculator. Simply input the amount, interest rate and term and the app displays you the amortization schedule (along with monthly breakups).
The app is not a visual delight but a good utility. And manages to beat a few paid apps on the AppStore 😉
Search for “Easyloan” in Cydia
Cydia is an Installer alternative, that Installs on Jailbroken iPhone 2.x… Info here