Price should always be a factor. But sometimes performance is more of a factor.
Ok, so well, I'd say the best spotter we can buy right now that I know of is the Trijicon Patrol 250XR MSRP $9k, street price mid to low $8k range.
https://www.opticsplanet.com/trijic...de-m250xr-4-5-8x60mm-thermal-weapn-sight.html
Heading down from there we have the Pulsar XP50 Helion street price mid $3k range.
The 250XR has optical magnification of 4.5x with 2x, 4x and 8x digital. The 2x and 4x are useable, the 8x less so. Because thermals are digital devices, you loose a lot of resolution with the digital magnification, but as I said, the 2x and 4x are still quite useful.
The Helion XP50 is 2.5x optical magnification and also has 2x, 4x and 8x digital.
https://www.opticsplanet.com/pulsar-helion-xp50-2-5-20x42-thermal-imaging-monocular.html
So, then besides price, you also have to think about what native magnification you will be needing. And for me, spotting is not the same as shooting. I might want to spot farther out than I will shoot, so I know what action to take, based on what I'm seeing.
So for long distance, the more magnification the better. The main functional trade-off is FOV. As your magnification goes up, your field of view goes down. The Trijicon 4.5x thermals are pretty rough to use inside 100yds and even rougher to use inside 50yds. So for close in they are NOT what you want. They are the long range thermal spotters.
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Now there are also 320, 336, and 384 thermals and here we are talking about the front end sensor, the microbolometer, NOT the rear end display. The front end my be 320 and the display might be 640. The frontend tells you how much thermal resolution you have, the display resolution tells you how many pixels you have to view those thermal pixels.
Trijicon doesn't make 320, 336 or 384 thermals because they are using the BAE OASYS cores which were made for the military. They are all 640. But Pulsar as a rich line of 384 devices including helion spotters. Here you trade resolution for price. The price goes down a little, the resolution goes down a lot. For long distance spotting, i.e. both detection AND identification, you need every advantage you can get. And hence I'd stick with the 640s for your purpose. Another plus of the 384 pulsars is the magnification also goes up.
And last but perhaps not least there are the older Pulsar Quantum spotters. These are 384 units, but have a lower price. Because they are older and don't have the bells and whistles of the Helions, like battery packs and video
https://www.opticsplanet.com/pulsar-pl77338-helion-xq30v-therml-bin.html