I can recommend you Dahua camera's. They are remarkably well made for their price and origin. They even have some fancy dynamic contrast and HDR-like features that increase visibility in shots where there is dark and light, or bright sunlight.
I've installed these cheap additional camera's at my parents, one Dahua dome camera for the driveway with POE, and a wireless bullet camera for the backyard.
DH-IPC-HDBW1320EP-028B
DH-IPC-HFW1235SP-W-028B
Both try not to access the internet by themselves. Any backdoors I am not aware, but it is your duty to make sure the internet can't reach them over your WiFi.
There are a foscam I didn't pick, but see for yourself in the attachment. Guess the foscam. This is about 60 days uptime.
Wireless really isn't intended for this. You need
constant 4 Mbit throughput for one good 10 fps 3 megapixel camera.
If you do not have better than -65 dbBm, the 802.11 rate goes down and the airtime goes up. This
really loads your WiFi, and you should use a separate radio. Or you have to reduce video quality, that makes the entire purpose of the camera questionable.
You should also use a separate SSID/WPA so any normal WiFi clients cannot intentionally malform the camera packets.
BTW, I tried installing this Firefox add-on to view the camera directly in the browser but it will not work for me. I would be interested if someone can help me get it to work,
You still need a VM with an old version of Internet Explorer (that never updates) to configure/view basically any cheap IP camera, due to plugins or Java, but when you see that Axis asks for their stuff. You will accept that.