These things are cool...I just finished hooking mine up, just have to mount the solar panel.
Walmart has the Birdfy brand on the shelves but I went with this one from Amazon...same price.....
https://www.amazon.com/dp/B0C7Z5NWJ5?ref=ppx_yo2ov_dt_b_product_details&th=1
Just click on the app and you have live video from a foot away from the feeder...or closer yet if you buy one of the feeders with the cam built in.
You can even use the app to identify what kind of bird it is. Just freeze the frame and it gives the info.
The one I bought has a built-in rechargeable battery and a good size solar panel for charging it.
It's easy to hook-up...took about 5 minutes.