Our toddler loves flash cards... well, loves dumping them all over the living room mostly. After getting tired of constantly picking them up I decided it was time to do something about it.
After buying some $1 packs of flashcards from Target Dollar Spot (love Dollar Spot!), I punched a hole in each one and reinforced them with hole reinforcement stickers before stringing them together with binder rings. If you don't have binder rings, you could also use a piece of ribbon or string.
And that was it - easy-as-can-be! Now I don't have a couple hundred flashcards thrown all over the living room, and they're super-easy to pack for car trips and travel!