Re: NV needed for pest control $600.00 budget
Check out the military surplus Ziess Orion 80 4x scopes. The seem to be selling in the $550 to $600 range. They are the current bargain in the NV scope dept. The are basically German surplus scopes. They take a STANAG mounting system, so you can get a rail adaptor from ARMS (#7 I believe) or UTG.
They are gen 1 scope and perform pretty nicely for the cost. They have several intensifier tubes (3 if I am correct) that are stacked on each other amplifiying the one in front of it. So you get pretty impressive gain, even for being just a gen 1 unit. Do not confuse gen 1 commercial units (which have a single intensifier tube) with a gen 1 military unit (usually 3 tubes).
But do your research on them. They are very sensitive to lighting and wash out/bloom if there is much lighting around. So it wouldn't work well if there are very many surrounding lights (street lights, parking lot lights, etc.). But if you got a dark area that you want to work in, these will work well. Where as using it as an observation unit in the suburbs won't work so well (lots of wash out & blooming).
They are also used surplus units. So it can be in excellent condtion or near the end of it's service life. They are also not much in the way of replacement parts or people to service them. Lastly, they are big and heavy.
Some other options are a PVS-4, which seem to run right around $900 or so. These are gen 2 scope and are very tough. They are pretty big and heavy, but perform well.
There is the M845 gen 2 plus units at $2K. They are very nice for a gen 2, but a big step up in price from the PVS-4.