Any ideas for my fiancee and me to save money on decorations at our wedding?

My fiancee and I are doing vintage theme for Montana at our wedding and looking for the best ways to save money. Mason jars were one idea we found. Does anyone know other great little decorations we could do? Also, has anyone found a way to save on food for catering? Thank you all.

EDIT: Thank you all so much for your suggestions and help! I will be taking many of them into consideration.