Are you looking for a Single Camera or a Camera with Recorder/NVR?

Disadvantages/Advantages Remote Camera
With a stand-alone camera, you can make short recordings along with an SD card and view the images live on your phone via the app.
This is a lot more economical because you do not need a Recorder/NVR the disadvantage is that you cannot record for much longer than 3 days depending on the resolution of the camera and the size of the SD card.

Disadvantages/Advantages with Recorder/NVR
With a Recorder/Nvr you can record ''depending on size of the HDD'' for up to several weeks continuously.
This can be advantageous if you want to go on vacation and record everything while you are away.