Just like the title says.  Wondering if they would be a nice entry-level (inexpensive) thermal option for a carbine.

They are very low res IIRC. Not a good option for anything IMO. The other major issue with thermal anything on a rifle is ID, which thermals suck at unless they are very high res and even then its not great.

Good advice.  For entry level get a scout tk or Leopold.

I am confused, are either of these rifle mountable for aiming?

A pal of mine brought his TPL a while back and I ran it here.
His had no reticle or aiming point and was the highest resolution of the breed that TPL offered at the time.

The screen is presented directly to the eye. There is no ocular lens assembly to magnify the screen or correct for vision.
Hence, you must hold the TPL at a distance you can see clearly and focus at that distance to see it clearly.

Many guys have knocked the TPL for that and its low resolution, but for a few hundred bucks I think it would be a wonderful addition to a rifle that's equipped with a light, or (better yet) coupled onto a flashlight. Maybe that sounds stupid to some, but to my way of thinking, it is FAR wiser to light up only areas you suspect hide danger, clear those, kill the light and then move and repeat, than it does to run your light continuously or too often while guessing.

I found that TPL to be useful for identifying as human most patches of heat visible through bushes from a human hiding there, within 100 feet or so.
If I were still working the street, I'd carry one and a spare. The things fit in your pocket and seem to be tough enough to use and are simple enough to hand to a person who's never heard of them, and he'll be able to run it.

The automatic contrast control of the one I used tended to adjust to a too-bright-screen level than I cared for. If there is a way to command the screen darker, I never found it.

For a carbine mounted thermal intended for aiming, I would look at a more sophisticated unit.

Sorry I got stuck on entry level...and missed "for a carbine"...

Just my opinion...but I'm not putting anything on my carbine that does not have solid and fast identification capabilities...anything less is a liability not an asset.

If you got the thermal bug (dont get me wrong thermal is cool as fuck and I love it)...but save up and get something with better capabilities if its going on a boom stick....YMMV.