I am a graduate student that receives a yearly stipend of approximately $28,000. In previous years, I have made my estimated tax payments on time with no problem. Last year, I owed the government about $240 after estimated taxes. This year, I made my first-quarter estimated tax on time. However, I did not make my next two estimated tax payments. In the beginning of January, I made a single payment to make up for the previous two missed payments as well as my last-quarter estimated tax installment. After adding all of this up, I still owe $335. I should also mention that I received a raise in the middle of 2008 (not sure if this matters). Is it likely that I will get hit with a penalty? Thanks