I have been using REO Link cameras for years. All the cameras I have installed (10 in total, 8 at one location, 2 at another) are IP Cameras, not wireless. However, their Argus 2 is wireless and battery operated. You can also purchase the solar panel to charge the batteries, so you only need wireless.
Installation is simple and does not require a computer or Network Video Recorder if you have a Smart Phone (you can use a computer or NVR if you want). Download the app, scan the qr code of the camera, give it a password and you are done. It is viewable from anywhere. You can also use a micro sd card to store video on, so you can review what was going on while you aren't watching. You can review video through the app. I have all 10 cameras connected to my app. If you have access to the wi-fi router, you can setup Port Forwarding to view the cameras in a web browser to get a larger view.
REO Link does not require a monthly subscription.
-Michael