Don't ask me why I have such an affection for sneaky hiding spots, but I do. This one is perfect for your little treasures, your cash, a key, etc. It's not too much of a pain to access, but I would probably use it for things that you don't need or want to access often.
Materials:
Jar with Lid
Toilet paper roll or similar
rice, beans, pasta, etc.
duct tape
cardboard (cereal box is good)
Tools:
Scissors
Step 1: Create the "safe"
Cut your tube down to size. Personally, I like it to be a small as possible so that the jar doesn't have to be suspiciously full. Cut out two card board circles. You want them big enough to provide stability, but small enough to squeeze into the mouth of the jar. Using duct tape, attach one to the bottom of the tube. Fill the tube with your secret loot and attach the other circle to the top.
Step 2: Bury Your Treasure
Line the bottom with a small amount of your "fill" to make sure that your secret is safe from every angle! Place your tube into the jar. The circles that you attached will make sure it remains stable while you fill it. Fille the jar until you can't see any signs of the tube.
Step 3: Put It Where It "Belongs"
Secret secret, I got a secret!
Hints:
Use a material that no one would "happen upon." In real life I could never use rice because we eat it like crazy and someone would find my stash quick. Buuuuut... I could totally use lima beans or lentils!