One great way to be creative without spending lots of money is by using recycled materials. Here are some tips on acquiring supplies in your community. (Note: Supervise young kid makers when gathering and reusing recycled materials.)
Plastic Bottles and Newspapers
Most households recycle a reasonable amount of these two items that you can use for projects. If you need more, friends and family are often a good source. Make sure plastic bottles are washed out with soap and water. Do not use bottles that contained volatile substances such as bleach, paint, or chemicals. Only use clean newspaper.
Cardboard is easily available but not always plentiful from your own home. Ask your local appliance store for empty boxes; they are likely to be clean and dry, unlike boxes from the grocery store. You may even find oversized boxes, perfect for building a fort with your child.
With some knowledge, planning and caution, you can find wood to reuse for your projects. When goods are shipped, they are often stacked on wooden pallets. Pallets keep goods off the ground and allow whole stacks to be picked up with a forklift. More importantly, pallets are often discarded after the shipping process and you can get them for cheap or free.
All pallets are treated in some way to keep them from rotting, and to discourage stowaway bugs on long ocean trips. However, it is not safe to use pallets that have been treated with chemicals -- sawdust full of chemicals is dangerous to breathe, and a woodworking project soaked in pesticide has no place in your home. But many pallets are simply baked in an oven to kill bugs, and are perfectly safe to use.
Pallets that are safe to use will be marked with the letters HT (for Heat Treated). Other letters and numbers indicate where it was produced. Be sure to avoid pallets marked with the letters MB (methyl bromide), as these contain chemicals. Avoid pallets that have no markings; there is no sure way to know if they contain chemicals.
With some precautions, you can reuse components found in discarded electronics, such as LEDs, motors, or switches. Battery-operated toys or CD players are good sources of reusable components that often work well on a safe amount of voltage, like 2 AA batteries.
Electronics that plug in -- like printers, clock radios, and computers -- are also generally safe, but their components may need higher voltage to function. The components may not work powered by a simple battery pack.
Devices that plug in may also have capacitors which store energy like a battery, and may still carry a dangerous charge when the device is unplugged. Avoid devices with large capacitors (a large capacitor looks like a cylindrical battery), or you can safely discharge them.
Do not use old televisions and computer monitors that do not have a flat panel. These CRT televisions and monitors store a dangerously high voltage charge even when disconnected, and the delicate glass can shatter and be dangerous.