Three places nobody will look ever for cash or cards or scrounge around in.
Step 1: Hiding Place #1
Do you know how loud fire alarms can be? Why mess with them unless you need to hide cash on a trip. Open and replace the battery with cash.
Step 2: Hiding Place #2
Find an Idiot proof book. Open to a chapter and place cash or card in the book. Close the book and place on a shelf.
Step 3: Hiding Place #3
Laundry is a no-brainer. Pile Laundry in a basket and pick some of the laundry and place valuables underneath