What's your m.o.?
Great for hobbyists and serious investigators alike, small, indiscreet cameras offer all kinds of advantages for detecting behavior without revealing your position You c or intent. You can find very inexpensive cameras online, but be forewarned that the image from an inexpensive camera may not hold up in court.
Sneaky camera dolls
If you are serious about a hidden camera, expect to pay about $300. For use in kids' rooms, these cameras can be purchased already installed in their stuffed pink elephant or kangaroo disguise. These are high-tech "teddy bear cameras" that deliver real-time images to a closed circuit television or even the Internet.
Some considerations
One can probably guess that these toy cameras will fool the sitter, but children may toss their toys about, ultimately burying your $300 surveillance equipment beneath more popular toys. Of course, setting the camera on a shelf as a decoration may be the solution, but it may tip off a sitter wise to this trend.
It may be smarter to purchase a small camera and learn a bit about wiring it up so you can place it where you see fit. Hiding it in a more stationary decoration like a flower pot or music box would be a safe assurance that it won't get tossed about and damaged.
Added bonus
When the child gets older, it provides a handy means to monitor behavior and establish an omnipresent, other-worldly knowledge about daily doings in your house.