Frugal Crafting -- Chipboard and Sandpaper
-- The cardboard in sticker packs make fabulous sturdy bookmarks. Either cover with gesso and paint or stamp, or you can cover them with paper and go from there.
-- Larger sheets make great postcard backgrounds.
-- The lighter weight cardboard works just great with most punches, particularly corner rounders, to take away the sharp (and potentially boring) points.
-- Use them as inexpensive cover and back pages for accordian books and cards.
-- Most have a nice shiny coating, which makes them great to use under projects you are stamping on to keep ink off of your work surface.
You don't need to spend a fortune on sandpaper. Odds are, you have plenty of what you need right around the house.
-- Old nail files are great for distressing paper.
-- Nail files will take sharp edges off wire, and smooth out areas where you've cut shanks off buttons and loops off charms.
-- The very fine and buff sides of nail files replace the harder-to-find extremely fine sandpaper, and can be dampened for use with polymer clay, or PMC.
-- An addition to useful nailcare items is saving old nail clippers. They may not cut your nails well anymore, but they'll still snap a shank off a button!