I usually store mine in my journal. I usually just paste a big envelope to the last page in my journal so I can just throw my old stubs in there.
Or sometimes I will paste them on their own page. These are maps and tickets stubs from a trip to Italy.
I also like the way my niece Kelli stores hers. She puts hers in an old photo album. Simple and easy.
How do you store your ticket stubs?