I use Momentum Cori cameras. https://www.amazon.com/dp/B092YB8NDP/ref=cm_sw_r_cp_api_glt_fabc_WWBB0CEK9N0GGY8NF80A You get 2 for $40 and the pack doesn’t have to be installed together. I gave one to my sister (we have separate apartments across town from each other) and they both work fine. They have the wifi option but also work with just an SD card and no wifi. You’ll have to research how much video an SD card can hold. The lower resolution the video is, and the bigger the SD card, the more footage can be saved. A general idea, don’t be surprised to only get somewhere around 8-12 hours before it rewrites the card.