Here at the Straight Talk blog, we’re all about the numbers. Whether we’re keeping track of what percentage of Americans have started saving for retirement or bringing you the latest statistics on ATM fees, we believe that when it comes to showing you the big financial picture, numbers don’t lie.

This week, we’re giving you a chance to prove your financial savvy by posing a number-related question each day. To play along, just put your best guess in the comments and then visit the following day for the answer. The topics will range from bank customer service to bank fees, so put on your financial thinking caps.

Our first question relates to something we talk about a lot on the Straight Talk blog: ATM fees. At Ally, we’re light on ATM fees. We don’t charge you to use any ATM in the U.S., plus we reimburse any ATM fees that other banks charge you nationwide. This is just another way we help our customers make the most of their finances.

But not everyone is so lucky. In fact, ATM fees are a significant source of revenue for banks. But just how big of a business is it?

In 2010, how much did Americans spend on ATM fees?

1. $580 million
2. $990 million
3. $2.8 billion
4. $7.1 billion

Leave us your guess in the comments and we’ll be back tomorrow with the answer and another question!