Practical budget tiers (and what I’d actually recommend):
Under $500: I’d look at digital NV monoculars only if you accept it’s an “observer” tool, not a movement tool. They usually need IR illumination to look decent. Good for spotting wildlife, checking a property line, or range steel at short distances. Avoid no-name Amazon units with inflated “8K/4K” marketing.
$500–$1,000: better digital units + a quality IR illuminator can be workable. Still, head-mounted walking is usually annoying (latency, narrow FOV, weird depth perception). If you’re thinking helmet later, I’d honestly save this tier.
$1,000–$2,000: this is where used image intensifier starts to make sense. A used PVS-14 from a reputable seller is the “buy once cry once” entry point. It’s also the easiest to resell if you upgrade. Ask for tube type (Gen 2+/3), photos through the tube, and whether it’s been serviced.
Thermal: awesome for detection, not great for navigation. If your goal is “see something hiding,” thermal wins. If your goal is “move and do normal tasks,” NV wins.
Brands to be cautious with: anything with sketchy warranties, unclear tube origins, or sellers who won’t provide through-the-tube images/specs. Reputable dealers matter more than a tiny price difference.