I'd like to keep around the 5k mark for the helmet,, mount and NVD. I figure that should be a very solid starting point.
I don't currently have a place to shoot at night, but I look to purchase property at some point in the future that will allow for that.
For now it'll just be for fun or if I find some night courses.
I've also seen a lot of people speak highly of the Photonis Echo for a budget option. I know they're not as good in complete dark though.
The echos are very nice, and have a really nice mixed lighting picture (arguably better than some of the gen 3 stuff). Another budget option is the XLSH line of tubes from Elbeit.
For $5k you can get a seriously nice setup.
Id budget about 1k minimum to outfit a firearm to place nice with your NVGs as well. There are budget options, but i would say $1k would get you setup pretty good.