All the tips on getting fabric are great! In addition to those, I found that you can get extra "mileage" out of your rotary blade if you take it out..put 1 drop (only 1) of oil on it and turn it over. You are good to go again!
Also..remember that your cutting mat has 2 sides...when one side is worn out- turn it over.
Buy your freezer paper for applique at Wally's or somewhere. You can use Parchment paper instead of that expensive applique sheet from the quilt store.
Use the cheap tablet tracing paper from Walmart for your Paper piecing vs. the printable foundation paper.
Clean the bottom of your iron with a used dryer sheet vs. expensive cleaners.
Use the mesh thingie from your bathtub (well- go buy a new one for a buck) to clean your cutting mat vs. the commercial cleaner.
Thats all I can think of at the moment, but theres more I know...