I work in the warehouse of a company that has TONS of corporate swag. I put that stuff in caches, not because I'm trying to get the company name out there (I could care less) but because it's free. I use:
corkscrews
pocket knives
stickers
lanyards
pens
bottle openers
flash drives
disposable ponchos (I love putting these in caches, you never know when you'll need one!)
and my favorite
minor league baseball tickets (which I also get for free)