I know nothing about IR, thermal, etc. scopes. Is there a low-cost thermal monocular or binocular that would be worth getting just to keep an eye on animals at my place. Will not be used for hunting in any way, shape, or form.

A FLIR Scout TK is about 500 bucks and would be my super low cost choice. Just get a new one so the internal rechargeable battery is fresh. Short range and not the greatest for definition but you will be able to find live critters in the dark. It goes up from there and you will get what you pay for.

I would just use the scope. A good qd will go to zero I have tried it.

Something less than $300...Bushnell Equinox Z to see 100-150 yards (Digital with IR Light) but tight FOV in my opinion and on a tripod much more stable picture. But usable over a red light. Red light with a regular scope is even cheaper and you can see a long ways with it. Spend $500 - $3K thermal monocular that can see much further (500 yards - 1,500 yards). The more money the clearer and longer distances you can see typically All about the use / budget.

Low budget. Would like to easily see deer at 100-150 yards. Trees aren't clear enough to see further than that.

What scope? I don't have a NV/IR scope

I have a no longer made flir PTS233 with an ADM mount and the buddies I hunt with have pulsars with bobo mounts. We all scan with them and then mount up when we find something. YMMV

Skip nightvision and go IR. I had one and thermal even on the lower end is outstanding

Can the thermal of IR see through light trees/brush out to 100-150 yards?

Interesting question…

So you’re going to be able to see stuff through some brush moving through the openings in the brush, but thermal cant see through a solid image like a tree.

Yes, you will have much better luck picking up animals in light brush/trees with a thermal than with NV. NV gets so much back-scatter from the brush that you're lucky if you can pick up the reflection from their eyes only. With the thermal you can see a small animal at 125-150 yards moving in the woods no problem.

Technically, no, it will not see through brush. It will see INTO brush via gaps in the foliage that NV won't pick out, but it will not see through anything solid (other than its own lens). It won't even see through window glass. However, THERE MUST BE DIRECT LINE OF SIGHT GAPS IN THE BRUSH FOR THERMAL TO SEE THE ANIMAL. Maybe you can see 125 yards into the forest that has little or no understory. Maybe you can see 5 yards into the forest that has a lot.

Yeah the brush I want to see through will definitely have gaps and lines of sight. It's not super thick up front. And a lot of it in the back might be tree trunks and stuff like that - so hopefully it can just see around those.