Don't bother with Gen 1.
If you don't mind the risk of not having a warranty you have a couple of cheaper options:
- Do your homework and buy used to save a ton of cash. Gen 3 PVS7's go for $1200 and up, PVS14's go for $1500 and up.
-Or build your own PVS7 or 14. Buy parts as your budget allows or you find deals. Finding the tube is the tricky part (again, do you homework, lots of homework before buying a tube, lots of crappy/shady sellers out there). Good videos on youtube about building them, its pretty simple if your mechanically inclined.
-Lots of folks in this forum cringe at the mention of digital night vision, but its come a long way and there are some cool home-brew options out there that can be built very cheap if you like to tinker. Its going to be similar to Gen 1 stuff, but with a good IR light it can be a useful tool. Then when you step up to real NV you have a cheap unit a buddy can use.
It all depends on your budget and what you want to do with the NV.....