Got the camera from Amazon for $26. There are others but this one can record events to local micro SD card. 2 ways radio works well. Very solid with internet. Doesn’t work with Echo Dot. Work with both Android and iOS. For a cheaper wifi camera that doesn’t have mircoSD card, also a good one.
We do have security camera all around the house but we haven’t gotten a few for the inside of our house. Fry’s had Trendnet IP camera TV-IP762IC on sale for $39, I went to get one to test it out. I was amazed with the technology these days and the hardware that cost so little.