While browsing in a Calgary store, I came across a great addition for my backpack, diaper bag and car's glove box. They are biodegradeable bags called the Code Red "Bag It" that come in a tiny red dispenser with a loop attached. I use mine as on-the-go diaper bags or garbage bags. I bought a pack of three dispensers -- 36 bags in all -- for just $9.99 at Kacz' Kids.
I love finding products like this that make my life easier!