Inexpensive generic brand wireless spy cameras are available on eBay.com and DHGate.com as of 2015. HomeSpy.com is a brand that offers a selection of economy-grade hidden cameras.
EBay offers a number of Wi-Fi and IP-based wireless spy cameras that are compatible with Android, Apple and PC. These cameras generally cost between $20 and $25 and are available without any disguised casing. DHGate offers a similar selection of generic cameras for prices between $25 and $40.
The wireless cameras available from HomeSpy.com are encased in household objects in order to disguise the camera. The economy-grade cameras on this website range in price from roughly $90 to $250.