The place where I keep my emergency fund is in U.S. Treasury I-Series savings bonds. Is there any reason why I wouldn't want to keep the emergency fund there? Is there a dynamic that I am not considering? Dave, Denver, CO

What do you recommend I get for my grandson who is in his third year of college and has no idea of how to manage his meager funds? William, Amherst, MA

Can my wife and I share one Roth IRA and contribute as much as $10,000 a year to it, or must we each have separate IRAs with the normal $5,000-a-year contribution cap? Jake, Madison, WI

Would you investigate the trajectory of a single dollar bill? Let me explain. So you go to the store and buy things, then you pay with a $100 bill. What happens to that note? In a nutshell, my question is: What is the route that a single bill takes? How does it circulate? How far can it travel? Homero, Sacramento, CA

I have been paying down my debt using the snowball method. I'm making great headway and have cut my debt load in half in 3 years. I'm at a point where I need to choose between a home-equity loan with a variable rate (currently at 4.24 percent but eligible for tax deductions) and a car loan at 3.5 percent fixed. Which makes more sense to pay down? Scott, Chatham, MI

I purchased a condo with a good friend approximately 5 years ago. We co-signed the mortgage and have had a great experience co-owning as friends. I recently got engaged and it's time for me (us) to move on. I'm having a difficult time finding an alternative to having my name removed from the co-signed mortgage. What options exist for us? Tom, Minneapolis, MN

There is an implication by those in the media that the Fed is essentially out of tools when it comes to lowering interest rates. Can the Federal Reserve lower the Fed Funds rate below zero? If so, what would be the implications for borrowers, savers and the macroeconomy? Richard, Marietta, GA

I am a graduate student in my mid-20s who has never had a credit card. While I have been able to get by without one, I have finally reached a stage in my personal and professional life where not having one has become a real inconvenience (when trying to reserve a rental car, for example). I would be grateful for advice on the cards, or kinds of cards, that I should seek or avoid for a first credit card — as well as whether I'm likely to receive one, and (if not) what I can do to make myself a better candidate. Stephanie, Minneapolis, MN

I have $30,000 and want to know where best to put it. Ultimately, I want to put it away for my three boys' futures. I want it to make something, however slowly, without risk. But, 0.4 percent? Is that really the best I can do? Joanna, Hammond, IN