You will get an image but the color will most likely be off. Once my Nana gave me one of her old cameras (antique by this point...bought new). She still had film in it. I did divelop it but, although there was an image, you couldn't make out what it was...I think it was land scapes. We estimated that the film was around 30 years old.
If you take it to a lab let them know that the color will be off. That way they don't waste a lot of time trying to corect something that can't be corected. Wall-Mart is a good idea; if you like anything that is on the film you can alway take it to be printed at real lab =)