As others have said, if your price is fixed at $1,500, about your only option is going to be used, and you'll need to search for a good deal and jump on it quick--and there are a lot of land-mines in the used market for NVDs, you need to know what you're looking at and know the technical details pretty well to make sure you're not getting ripped off or overwhelmed by techno-babble that the seller is hoping that you simply won't understand and go with it.
That being said, if you know what you're looking for, you can do quite well, I'll be the first to admit that I've gotten some great deals on used gear, but I am/was familiar with the technology market before I tried buying used stuff, it's one of those unfair realities that the folks that usually get the best deals on used stuff are the people who already have enough knowledge and experience to not need to buy used stuff.
Now--if you're willing to increase your budget by a little bit, you may open up some more options, and there are some fairly competitively priced Gen. 2+ units if you can't swing the budget increase to go with a new Gen. 3 device.
Some key things that might be worth clarifying:
The PVS-7 and similar format goggles like the Armasight are what are referred to as "biocular" devices, they've still only got a single tube, but they use a splitter to project the image to two eyepieces, giving the "illusion" that you can see with both eyes, but really, you're seeing a single light amplified image in both eyes, so you still won't have any kind of depth perception or added situational awareness. The simple reality of biocular devices was that the military wanted to cut costs on night vision goggles, so moved from the dual-tube PVS-5 to the single-tube PVS-7, but wanted to "pretend" like they were still goggles. Pure cost-cutting measure, and arguably made sense at the time, given the cost of image intensifier tubes for infantry use the single tube was considered good enough.
At the same time, biocular devices pretty much weigh almost the same as a set of binoculars, are larger and more complex due to the splitter and associated hardware, more lenses, etc., with really none of the advantages of binoculars. This is why PVS-7s tend to sell for a lot cheaper than PVS-14s, especially on the used market, and why so many people are saying the PVS-7s suck. That being said, especially on the used market, they're often the cheapest way to get into a high-spec tube, so take that for what it is.
In the military, the PVS-7 has largely been replaced in front-line use by the PVS-14, a monocular night vision device (MNVD), which still uses a single tube (but different format) which is much lighter and much more versatile than the PVS-7.
Finally, a note on dominant versus non-dominant eye use of an MNVD, and the use of NV-compatible red dot sights.
The older paradigm is/was to use the MNVD over the non-dominant eye, and if necessary to use the day optic much like an occluded eye sight. This is the way I was taught coming up, and it is still a commonly taught TTP, a lot of guys did a lot of fighting running MNVDs like this for a lot of years in a lot of shitty places.
That being said, the paradigm has been shifting to the increased use of MNVDs over the dominant eye, and to use NV-compatible sights and "passive aiming." Some of this is driven by changing threat situations (it is no longer a given that U.S./coalition troops are the only ones with effective NV technology), some of this is driven by changes in other equipment/technologies, such as the increased use of red dot sights on pistols, and some of it is driven by physiological factors that have been brought into sharper focus by the almost universal use of binocular night vision devices (BNVDs) by those on the sharpest end of the spear--while a full explanation of all these factors is best left for another time, the point is that paradigms and TTPs for the use of optics, lasers, and NVDs has changed a bit. I know there will be a lot of folks who have done it another way who may protest my saying so and will want to argue, but as with anything else, TTPs are not static, and continue to evolve over time.
While the use of IR aiming lasers is still quite relevant and quite common, it's becoming increasingly common to use NV-compatible optics, particularly red dots in conjunction with dominant-eye mounted MNVDs or with BNVDs to engage targets without presenting an active IR signature. In many cases, the use of a riser or high-mount for the optic is recommended to make it easier to align the NVD with the optic. While this is far from universal, one need only look at the increasing proliferation of high-rise optics mounts like the KAC "Skyscraper" and 1.93" height mounts to see that it is becoming more common.
Nevertheless, no one is advocating for ditching IR aiming lasers and illuminators completely, IMHO, a good "24/7 rifle" has both an IR laser/illuminator and an NV compatible optic, as well as sidearm with an RDS, and users should train both active and passive aiming techniques. At the same time, if cost is a factor and/or you need to buy accessories incrementally, I can run a carbine with a head mounted NVD and a high-mounted NV-compatible RDS almost as easily and quickly as one with an IR laser, with more "crossover" between day/night engagement techniques, and if you were to ask me which to get first, the IR laser or a day/night sight, I would say a day/night sight with a good mount would give you more capability day/night than an IR laser alone.
~Augee