Cheapest I can find is like $150 and I'm not even sure if those work
Buddy, for $5, a flashlight, toy store binoculars, and some green film, I can make you the baddest infiltrator this side of the median line
If possible for your use, I'd look into thermal. I got into digital thermal a couple years ago but it felt like the prices were about to go down quickly for decent equipment.
There's a lot of overlap between the ranges that night vision and thermal see (IR) so you can often get much much better digital images from a thermal sensor than you can with similarly priced "night vision" equipment in my experience. Everything has slightly different temperatures, even fractions of degrees, so you can make out features in plant leaves and things from a couple hundred meters.
About ten years ago, I was gifted a consumer/toy level set of NVGs, and the were quite useful, even at that price point (~$100). Considering that was quite a while ago, they've hopefully gotten better
