"Things have been missing and I know it's her, but I want to have something where it's beyond question," the man said. "It's good to be able to look in on my own home."
The other buyer, who operates a contracting business, said he wanted to safeguard landscaping equipment from theft.
"I'm not looking to be spying," he said. "But if there's an incident, we'll have a record of it."
Cheaper pricing has encouraged some novel uses for the camera technology. Some pet lovers, for example, have hooked home surveillance cameras to the Internet so they can look in on their dogs and cats while at work.
Michael Scott, spokesman for D-Link Systems Inc., a leading maker of remote cameras and wireless technology, said some buyers use Internet-accessible cameras to keep an eye on vacation homes.
Creative applications are also being found for GPS devices, spy gear vendors said. Parents install them in automobiles to keep track of where their teenage children drive and how fast. Suspicious married people hide them to learn if spouses are making secret rendezvous. GPS devices can also be given to children and early Alzheimer's patients in case they wander off.
GPS services can be expensive. Active devices that permit real-time tracing typically cost $600 to $800 and have monthly service fees of $20 to $30, said Leif Kehrein, owner of The Spy Shop. That cost, he said, deterred a prospective customer from buying one to track the movements of her wandering cat.
Ironically, rising sales of surveillance equipment are spawning another trend: rising sales of anti-surveillance gear. Kehrein recalls one instance where a husband bought a wireless camera to track the activities of his wife. A few weeks later, the wife became a customer too.
"She bought a wireless detector to find out where the camera is," he said.