1999 Mitsubishi Galant Stumped

While driving my galant one day it literally just stopped going forward. The car will turn on but when put into gear nothing happens. We have checked everything, and had it checked about 2 months before this happened. We have no idea while it won't go into gear and are stumped. I don't have the money to rebuild the whole transmission so we are hoping it might be something more simple that we missed. Thanks!