I am looking for a movie, for my wife.  All she can tell me is that the movie is from the 80s or early 90s and is about a young girl (11 or 12) that somehow travels back in time to the Great Depression and tries to stop it from happening, or something along those lines.  Any help that can be given is appreciated.  Thank you!

I'm not sure if this it...how about the 1985 movie The Journey of Natty Gann?

Split Infinity, 1992.

Since IMDB doesn't have a synopsis, I'll use someone else's:

"A.J. is an enterprising high school girl who runs a concessions business in the school. This is not a bad thing. What is a bad thing is that A.J. is obsessed with money and all the things it can buy, while being ashamed of her sensible family and out-of-the-way farm. She confides in her grandfather how she hates the farm and wishes she could move away and "be somebody".

Later that evening, A.J. is in the loft of the old family barn and the railing breaks, sending her tumbling to the ground floor.

She wakes up to a sour old schoolmarm asking her a question, calling her "Amelia Jean" (which was also her great-aunt's name). She then realizes she's in an old schoolroom surrounded by people in old-fashioned dresses and coveralls, understandably freaks out, and then sees a calender marked with the year 1929.

A.J. discovers she's actually taken her great-aunt Amelia Jean's place in the past, right before the stock market crash that led to the Great Depression. She meets the cocky young Frank - that is, her wizened grandfather as a young man - who is trying to sell the farm to make a good bit of money. He's pretty much a jerk, and obviously doesn't believe what A.J. tries to tell him about the stock market crash, so it remains to be seen if he will listen to her and not sell the farm, and if she will be able to get back to her own time.

In the meantime, A.J. has to go to school and interact with other people...in 1929. Somewhat of a disaster."

- Synopsis excerpted from Rebecca Mikulin's review of Split Infinity.