I spent about $10 buying a bunch of different tiny things (beads, clothespins, paper clips, dice, etc.) to make I Spy bottles. Best money I think I've ever spent. Ellie has spent literally hours playing with the extras.
We've used muffin tins, funnels, scoopers and different cups and bowls. She's sorted them by type and by color, practiced pouring, listened to different sounds the beads make, and put them ALL in her crib.
Building with spools
Trying them in one of the cheap organizing boxes I got