I've been looking for cheap optionally non-cloud camera recently and cycled through 15 different vendors on amazon buying, testing, probing, and returning.

Here's what I found.

If you don't want to pay a lot, there's something called "wansview" which is a white-label to a number of cheap amazon cameras (sub $20). You can do ONVIF and RTSP on any of the wansview firmwared devices and then knock them off the internet to keep it local.

Most recommendations of cameras for things like home assistant point to things at rolls-royce prices (~sometimes 20x the cost of the cheap consumer ones).

You shouldn't have to pony up a 2,000% markup for the feature "has tcp port open for rtsp"

Anyway, here's some wansview firmwared cameras

https://amazon.com/dp/B0CBBT5RMP $14

https://amazon.com/dp/B07QKXM2D3 $18

https://amazon.com/dp/B0B1T8T1WD $17

https://amazon.com/dp/B0DN1W3SWM $12.5

There's probably more

You can do on-device storage and stream over network ... no cloud subscription needed and no huge price tag.

If you're looking for others, you don't even need to buy the camera and check. Just scroll through the marketing jpegs on the amazon page. If they have screenshots with wansview you're good.

It's the only vendor I've found that does this.

This should be long term stable. If they decided to remove it you'd have to manually "upgrade" the firmware - which you won't have to do.