Aluminum and Lye (Sodium Hydroxide, NaOH) make an effective hydrogen generator. We used to play with this all the time, putting out copious amounts of H. Just be sure to use a large heat-proof container as it gets quite warm, and be cautious of boil-overs, allow plenty of room in your generating container for foaming.
Both materials are cheap, both are easy to obtain. Using thin aluminum foil cut into bits reacts the fastest in a lye solution, you might want to try aluminum cans for a more extended reaction. For a reaction vessel I might suggest a 5 gallon water jug. To slow down the reaction cool it down, or dilute the lye solution more the next time.
